i ' ‘ ‘ 4 } : ’ », ayy oe ’ ‘ NIT ANOA ONE ENDO 1 & Wat ea tasty att IAPWS Veena eTeR ae by “hi yee eee HURON kt MAYA EPS NTR ey aryl ‘ ; ‘ ’ Ad att qi i ; ' : " 1 4 ‘ ‘ " , ¥ seh he \ , \ , ; ys ea alhtats ‘ 4 al ° . t Af ' ; De} ! italy . ' Mt : RB eal oat eth el Ralsatt { J 4 4 a te Tgaye 8 Ls pridids, ea Mis bh + Ti eee ere a) Judit! onveiant* brea ope eI ’ Peas Rd nites ' “4 x if) ys ay RYU Se bya wet Pg ath wh hte Ay A IOSHLINS S3IYVYE!IT LIBRARIES SMITHSONIAN ‘df ep~ae™ (NOSHYY - Vie NS i Wasi a a ee NvI SMI NVI SM NV! NOILMLILSNI NVINOSHLIWS SSIYVYEIT LIBRARIES SMITHSONIAN INSTITI ES Ni LIBRARIES OMI! NOILNLILSNI NOILANLILSNI NOILNLILS ® L!S3RARIES SMITHSONIAN INSTITUTION NOILNLILSNI NVINOSHLINS S3ZIuYX 4 SaluvVUGIT LIBRARI INSTITUTION INSTITUTION INSTITUTION NOILNLILSNI NVINOSHLINS S3!1uYvVudl) INSTIT NVINOSHLINS S3IYVUYdIT LIBRARIES NVINOSHLINS S3l1avagi- n” a Z = 2 z § S r=. S - i a Or: < BS = z = = > : = = = 4 w z ” a Tp) LIBRARIES SMITHSONIAN INSTITUTION NOILNLILSNI NING 1 uy — Ww = as 5 = me . or + n = o ASS poe 2 3 ra > NY = > ra Viz Le: > = a BN ¥ . : 2 : ‘ U)" fe poe a) WN ; cen oe D z a SMITHSONIAN LIBRARIES INSTITUTION NOILNLILSNI NVINOSHLINS S31 UX ap) ” = z z t, = . =| z x a till py, = =< ro} \ B te Gis a SA 8 2 wns 2 hil Xs = a . SS 2 ee 4 fi =; SS SS » SS . ~ = aay ae Z NOILALILSNI NVINOSHLINS S3I1¥YVYd!I1 LIBRARIES SMITHSONIAN INSTIT = a F Zz ” ‘ ” 4; rap) = Y — Vth A c UN e hie ce Oo AS 2) e) Za A rs LIBRARIES SMITHSONIAN INSTITUTION NOILNLILSNI NVINOSHLINS S31 4\ SAINVUSIT LIBRARIES JOSHLINS S3IYVudl LIBRARIES SMITHSONIAN = a = 6 “«. § E E WY = riff = Ux F - “GY - - w Ly : 2 le Z By NOILNLILSNI_ NVINOSHLINS, S31NVUGIT LIBRARIES, SMITHSONIAN INSTIT Sot: = . Le= =e f == Wo > VY S + Bi a ZN. a 0OODZGZ = WW x im Bs ie ad “Nosy ALILSNI_ NVINOSHLINS NV pit oa S3!IYVYEIT LIBRARIES SMITHSONIAN INSTITUTION ES SM NV SM NV NOILALILSNI NOILNLILSNI LIBRARIES RARIES SMITHSONIAN INSTITUTION NOILALILSNI NVINOSHLINS S31YVudIT SaluVvVYaIT LIBRARI INSTITUTION NOILNLILSNI INSTITUTION INSTITUTION INLILSN!I NVINOSHLINS S3IYVed!IT LIBRARIES we SMITHSONIAN. INSTITUTION NVINOSHLINS S3I1YVNal) SMITHSONIAN NVINOSHLIWS SMITHSONIAN SMITHSONIAN RARIES SMITHSONIAN INSTITUTION NOILNLILSNI NVINOSHLINS S3INVUYSI- NOILANLILSNI LIBRARIES LIBRARIES Z Ay LNLILSNI NVWINOSHLINS S3!YVvVYaIT LIBRARIES SMITHSONIAN INSTITUTION YY, \ SS \ RARIES SMITHSONIAN INSTITUTION NOILALILSNI NVINOSHLINS SSIYVYEI Wy, INSTITUTION INSTITUTION NOILNLILSNI SJIYVUGIT LIBRARIES ssiuvaeit INSTITUTION SA1uvyudly N NVINOSH.LIWS NVINOSHLIWS LNLILSNI_ NVINOSHLIWS hy NVINOSHLIWS yg SMITHSONIAN S3IMYVYNSIT LIBRARIES S NOILNLILSNI NOILNLILSNI NOILNLILSNI RARIES SMITHSONIAN INSTITUTION NOILNLILSNI NVINOSHLINS S3J1u¥Vvugl S3IYVNSIT LIBRARIES SMITHSONIA INSTITUTION INSTITUTION INSTITUTION INLILSNI NVINOSHLINS S31YVUSIT_LIBRARIES SMITHSONIAN INSTITUTIO! zZ 2 zZ ae < x " < We ii Pri go i BS 1 Pris 4 wn “P » Ss ‘, 2 t (@) ae \, bE oy dD We” 2 EE 33] 2 We » i ae tem, 4 fut bey eg Dy al y y ai f ms fe 9 . a a a | : ¢ mn 7 - 2 ; : a a . ’ A r ‘ & q z ier a | ; = 5S 640,F 7-3 [39 36 ie BULLETINS OF AMERICAN PALEONTOLOGY VOL. 65, 1975 Biology and Paleobiology of Ostracoda A Symposium University of Delaware, 1972 Pea ah Sat iw ZENNTHSONTA WS, { APR}y4 1975?) > CiBMANILS 2 ‘ fOr" Grand pre \ = ows oT AR aie tes = 7 1905 1899 BIOLOGY AND PALEOBIOLOGY OF OSTRACODA A SYMPOSIUM UNIVERSITY OF DELAWARE 14-17 AUGUST, 1972 FREDERICK M. SWAIN, Eprror University of Delaware; University of Minnesota LOUIS S. KORNICKER AND ROBERT F. LUNDIN ASSOCIATE EDITORS National Museum of Natural History Arizona State University Published by PALEONTOLOGICAL RESEARCH INSTITUTION IrHaca, New York 1975 BULLETINS AMERICAN PALEONTOLOGY VOLUME 65, NUMBER 282 Library of Congress Card Number: 73-90558 THE SYMPOSIUM VOLUME IS DEDICATED 10 BETTY KELLETT NADEAU AND FRANK McKIM SWARTZ PREFACE Three previous meetings of Ostracoda workers were held in Naples, Italy, organized by H. S. Puri; in Hull, England, arranged by J. W. Neale; and in Pau, France, assembled by H. J. Oertli. It has been a pleasure to welcome the group of Ostracoda workers to this latest meeting at the University of Delaware. The pattern of organization of the three earlier meetings was generally followed in the present one. The field trip to the middle Miocene outcrops of the Calvert Cliffs, Maryland, was led by Mrs. Dabney Hart and Mr. C. W. Hart, Jr., who also provided the guidebook for the trip. The post- meeting field trip in the Holocene sediments of southern Delaware was led by Dr. J. C. Kraft, and that in the Paleozoic rocks of the Appalachian Mountains was led by Dr. A. L. Guber. Mr. D. L. Zalusky assisted with the Appalachian trip. A short field trip to the Upper Cretaceous outcrops along the Chesapeake and Delaware Canal, Delaware, was led by Dr. T. E. Pickett. Dr. and Mrs. Pickett also entertained the group at their home following the field trip. Dr. Frank B. Dilley, Associate Provost for instruction at the University of Delaware gave a welcoming address at the opening of the symposium. John C. Kraft, Chairman of the Geology Department at the University, secured the University Funds necessary to hold the Symposium. These funds were made available from a Unidel Grant for the University of Delaware. Funds in support of the publication of this volume were pro- vided by the Smithsonian Institution on behalf of Drs. R. H. Benson and L. S. Kornicker. Dr. H. V. Howe provided a personal contribution in support of publication. Louis S. Kornicker and Robert F. Lundin have provided valu- able assistance as Associate Editors. Claudia Converse also assisted in editorial matters. Annette Craig aided in preparation of final drafts of tables and other typing. Mrs. Nancy Gerrity, secretary of the Geology Department, assisted greatly with administrative matters. The following Uni- versity students aided in many aspects of the meeting: John Sher- man, Alan Crossan, Robert Caulk, Xenia Goluvchenko, Roger Moose, Christine Dutton and James Pittman. PREFACE I am sincerely grateful to all of the individuals named above for their assistance and support. It was a great pleasure to have in attendance at the Symposium two of the foremost American workers on Ostracoda: Mrs. Betty Kellett Nadeau and Dr. Frank McKim Swartz. This volume is dedi- cated to them in sincere appreciation of their contributions to the study of fossil Ostracoda. Dr. Henry V. Howe, who attended our symposium and was co-author of two of the papers appearing in this volume, died September 27, 1973. We deeply regret the loss of our friend, col- league, and mentor. Newark, Delaware F. M. Swain November, 1973 PARTICIPANTS Baker, Mr. James H., Department of Biology, University of Houston, Houston, Texas 77004 Bate, Dr. Raymond H., Department of Palaeontology, British Museum (NH) London, SW 7, England. (Not attending; paper read by J. W. Neale.) Benson, Dr. Richard H., Room 204 E, National Museum of Natural History Smithsonian Institution, 10th and Constitution Ave., N.W., Washington, D.C. 20560 Berdan, Dr. Jean M., U.S. Geological Survey, Washington, D.C. 20242 Bertels, Dr. Alwine, Ciudad Universitaria, Fac. Ciencias, Univ. Buenos Aires Pabellon II-la piso, Dept. Geol. Ciencias, Buenos Aires, Argentina. (Not attending; paper read by R. C. What- ley.) Bless, Dr. M. J. M. Geologisch Bureau v.h. Mijngebeid, Akerstr 86-88 Heerlen 5200, The Netherlands Bold, W. A. van den, Dr., Department of Geology, Louisiana State University, Baton Rouge, Louisiana 70803. (Not attending; joint paper with H. V. Howe read by Dr. Howe). Brondos, Mr. M. D., Department of Geology, University of Kansas, Lawrence, Kansas 66044. Cadot, Mr. Meade, Department of Geology, University of Kansas, Lawrence, Kansas 66044. (Not attending; paper read by-R. L. Kaesler as joint author.) Carbonel, Dr. P., Laboratoire de Geologie et Ocean., University de Bordeaux, 33 Talence, France. (Not attending; paper read by J. E.. Hazel.) Carbonnel, Dr. G., Univ. Lyon-I-Claude Bernard, Dept., Sci. de la Terre, 15 et 43 boul. du 11 Novembre 1918, 69 Villeurbanne, France. (Not attending, but submitted paper. ) Christensen, Dr. Ole Brunn, Geological Survey of Denmark, Thoraves 31, 2400 Kobenhavn NV, Denmark Damotte, Dr. Renée, Centre National de la Recherche Scientifique Laboratoire de Micropaléontologie, Université de Paris VI, Paris, France. Danielopol, Dr. Dan L., Limnologische Inst., Vienna, Austria 1090. (Not attending, but submitted paper.) PARTICIPANTS Delorme, Dr. L. Denis, Inland Waters Branch, 3303-33rd Street NW, Calgary 44, Alberta, Canada Dépéche, Dr. F., Laboratoire de Micropaleontologie, Université de Paris VI, Paris, France East, Miss B. A., Dept. Chem. Eng-Tech., Imperial College, London SW7, England. (Not attending, paper read by J. W. Neale.) Echols, Dr. Dorothy J., Department of Earth Sciences, Washington University, St. Louis, Missouri 63130 Gerry, Mr. E., 61170 Tel Aviv, Ramat Aviv, P O B 17081, Israel Gio-Arguez, Sr. Raul, Instituto de Geologias UNAM, Mexico 20 D.F., Mexico; and Sra. Gio-Argaez Grigg, Miss Ursula M., Department of Geology, St. Marys Uni- versity, Halifax, N.S., Canada Groos-Uffenorde, Dr. Helga, D-3400 Géttingen, Geolog.-Palaont. Institut, Berliner Strasse 28, Germany Guber, Dr. Albert L., Department of Geology, The Pennsylvania State University, University Park, Pennsylvania 16802 Hart, Mr. C. W., Jr., Academy of Natural Sciences, 19th and the Parkway, Philadelphia, Pennsylvania 19103 Hart, Mrs. Dabney, Academy of Natural Sciences, 19th and the Parkway, Philadelphia, Pennsylvania 19103 Hartmann, Gerd. Prof., Dr., Zoologische Institut and Zoologisches Museum der Universitat, 2 Hamburg 13, v. Melle Park 10, Germany, and Frau G. Hartmann-Schroder. Haskins, Dr. C. W., Robertson Research Laboratories, Tyn-y-Coed, Llanrhos, Llandudno, N. Wales, U.K. Hazel, Dr. J. E., U.S. Geological Survey, E-501 U.S. National Museum, Washington, D.C. 20244 Howe, Prof. Robert C., Department of Geology and Geography, Indiana State University, Terre Haute, Indiana 47809. (Not attending; paper read by H. J. Howe.) Howe, Prof. H. J., Department of Geology, Purdue University, Lafayette, Indiana 47907 Howe, Prof. H. V., Dept. Geological Sciences, Louisiana State Univ., Baton Rouge, Louisiana 70803 and Mrs. Howe Ishizaki, Dr. K., Inst. Geol.-Paleont., Tohoku University, Sendai, Japan PARTICIPANTS Kaesler, Dr. Roger L., Department of Geology, University of Kansas, Lawrence, Kansas 66044 Keen, Dr. Michael Charles, Department of Geology, University of Glasgow, Glasgow W 2, United Kingdom Keyser, Mr. D., Zool. Institute und Museum der Univ. Hamburg, 2 Hamburg von Melle Park 10, Germany Kornicker, Dr. L. S., National Museum of Natural History, Smith- sonian Institution, 10th and Constitution Ave. NW, Washing- ton, D.C. 20560 Kraft, Prof. John C., Department of Geology, University of Dela- ware, Newark, Delaware 19711 Liebau, Dr. Alexander, Geol.-Palaont. Inst., D-4, Tiibingen, Ger- man Loffler, Prof. H., Limnological Department, University of Vienna, Bergasse 18, Vienna, Austria 1090 Lundin, Dr. Robert F., Department of Geology, Arizona State Uni- versity, Tempe, Arizona 85281 McKenzie, Dr. K. G., School of Applied Science, Riverina College of Adv. Ed., Wagga Wagga, NSW, Austrilan 2560. (Not at- tending, paper jointly with R. L. Kaesler, read by R. L. Kaesler. ) Maddocks, Dr. R. F., Geology Department, University Houston, Houston, Texas 77004 Moguilevsky, Dr. Alicia, Department Biol., Facultad Ciencias, Ciu- dad Universitaria, Pabellon 2, piso 4th, Cabital Federal BS, AS Argentina. (Not attending, paper jointly with R. C. What- ley, read by R. C. Whatley. ) Moyes, Prof. Jean, Institut de Geologie, Faculte des Sciences, 33 Talence, France. (Not attending; paper read by J. E. Hazel.) Nadeau, Mrs. Betty Kellet, Westview Lane, Norwalk, Connecticut 06854 Neale, Dr. John W., Geology Department, Hull University, Hull, Yorkshire, England Oertli, Dr. H. J., SNPA Centre de Recherches, 64 Pau, France, and Mme. Oertli Petersen, Dr. L. E., Department of Geology, Arizona State Uni- versity, Tempe, Arizona 85281 PARTICIPANTS Peypouquet, Dr. J. P., Laboratoire de Geologie, Faculte des Sciences de Bordeaus, 351 Cour de la Liberation, 33 Talence, France. (Not attending; paper read by J. E. Hazel.) Pollard, Dr. J. E., Department of Geology, University of Man- chester, Manchester, England. (Not attending; paper read by M. J. M. Bless as joint author. ) Price, Mr. L. Greer, Department of Earth Sciences, Washington University, St. Louis, Missouri 63130 Puri, Dr. Harbans S., Bureau of Geology, P.O. Box 623, Tallahassee, Florida 32304 Rafle, Miss Mary Ann, Dept. Earth Sciences, Washington Univ., St. Louis, Missouri: 63103. (Not attending; paper jointly with Dr. Echols and Mr. Price, read by L. Price.) Reyment, Prof. R., Paleontologiska Institutionen, Uppsala Univer- sitet, S-751, 22 Uppsala, Sweden Sandberg, Dr. P. A., Department of Geology, University of Illinois, Urbana, Illinois 61801 Schulz, Mr. K., Zool. Institut und Museum der Univ. Hamburg, 2 Hamburg, von Melle Park 10, Germany Siddiqui, Dr. Q. A., Department of Geology, St. Marys University, Halifax, IN/S...Canada Sohn, Dr. I. G., U.S. Geological Survey, Washington, D.C. 20244 Swain, Prof. F. M., Department of Geology, University of Delaware, Newark, Delaware 19711; Department of Geology, University of Minnesota, Mpls., Minn. 55455 Swartz, Dr. F. M., 6665 North Donna Beatrix Circle, Tuscon, Arizona 85718 Uffenorde, Dr. Henning, D-3400 Gottingen, Geol.-Palaont. Institut, Berliner Str. 28, Germany van Morkhoven, Dr. F. P. C. M., Shell Oil Co., Box 60775, New burg 13, Papendamm 3, Germany Vesper, Dr. B., Zool. Institut u. Museum, Univ. Hamburg, 2 Ham- burg, von Melle Park 10, Germany Watling, Mr. Les, Field Station, University of Delaware, Lewes, -_1*Delaware 19958 Whatley, Dr. Robin C., Division Micropalaeontologia, Facul. Cien- cios Nationales y Mineo, Nat. Univ. de la Plata, Paseo del Bosque, La Plata, Argentina; and Department of Geology University College of Wales, Aberystwyth, G. B. CONTENTS Frontispiece Page PRCA OMG DARE 6b sbree ink oe: RE AO DRAG acl « 2 Ereraeoe “itis et One Uk Ns ad eh OY, 3 I CINALICSMART De tity Nn Penge Pee noice A eee Me 5 I. Morphological and physiological studies Benson, R. H., Morphologic stability in Ostracoda ..... 13 Danielopol, D. L., Remarques sur la diversification morphologique de trois nouvelles espéces d’Elpidium GOstracau a atGMas oh. temps ga neta oer 47 Howe, R. C. and Howe, H. J., Species determination of molts from the Shubuta Clay of Mississippi .......... 61 Liebau, A., The left-right variation of the ostracode (OVATENIAY SI 01 eh ee ane et Nene Al ap ie i Renee ae Newry > 2 77 Lundin, R. F. and Petersen, L. E., Thlipsura Jones and ldoll:-a ‘redescription of the type-species —.. 2-2... -. 87 Bless, M. J. M., and Pollard, J. E., Quantitative analysis of dimorphism in Carbonita humilis (Jones and Paty) Prete eet ES: Fr LIS, Came OE”, Rib. von eae: 109 II. Environmental aspects Kornicker, L. S., Spread of ostracodes to exotic environs bn Cralisplamtedsoystersy CONE SLE de yeaa =. 129 Reyment, R. A., Canonical correlation analysis of hemi- cytherinid and trachyleberinid ostracodes in the Niger Delta 2. cipeeterlaceatiekinw- ob ables ps ee eee 141 Uffenorde, H., Dynamics in Recent marine benthonic ostracode assemblages in the Limski Kanal (northern POAT SED) oso Nes esas yet SA 147 CONTENTS Echols, D. J., Price, L. G., and Rafle, M. A., Variations in fresh-water Ostracode populations from lakes in St. Louis ‘County, Missourt.....02 20.4) +3) Whatley, R. C. and Wall, D. R., The relationship be- tween Ostracoda and algae in littoral and sublittoral MAaTINe ENVIONMENtS, 2-2 82.65.46 Ge Ce ee eee Vesper, B., To the problem of noding on Cypridets torasa>Chones, 1850) sie OCA «2.2. bo, a Oe eee Sohn, I. G. and Kornicker, L. S., Variation in predation behavior of ostracode species on schistomiasis vector Snails RIG TENE Lee PIPE RUE cot de ee Kaesler, R. L., Morphology of Cypridopsis vidua (O. F. Miiller): Variation with environment .............. Ishizaki, K., Morphological variation in Leguwmino- cythereis ? hodgu (Brady), Ostracode (Crustacea) from. Japan, 22302 ab sales sis ORIN ae. aoe ee III. Stratigraphic and ecologic studies of fossil Ostracoda Damotte, R., Ostracodes Cenomaniens du Bassin de Paris: quelques resultats d’ordre Paleoecologique et Paleopeopraplique ”.) 2). gi Crs bys ane oe Keen, M. C., The paleobiology of some upper Palaeo- gene fresh=water Ostracodes.-.......e. 4.455 ect oeee Carbonnel, G., Le facteur lisse chez certains ostracodes tertaires: un index de paléotempérature ............. Howe, H. V. and van den Bold, W. A., Mudlump Ostra- COUR ee ee ee ent eee ee Bertels, A., Ostracode ecology during the Upper Cre- taceous and Cenozore in“Arpentina ..>...-.-- 42-529 CONTENTS 11 IV. Zoogeographic and ecologic studies of Holocene Ostracoda Hartmann, G. and Hartmann-Schréder, G., Zoogeogra- phy and biology of littoral Ostracoda from South inca, onpola, and Mozambique 1 a ee 353 Siddiqui, Q. A. and Grigg, U. M., A preliminary survey of the ostracodes..of Halitax Inlet oicn:', <5 sone le 369 Neale, J. W. and Howe, H. V., The marine Ostracoda of Russian Harbour, Novaya Zemblya and other high latrende: faunas: af. Lab iae., fericel site bed sis vdlieton. 381 Loffler, H., The evolution of ostracode faunas in alpine and prealpine lakes and their value as indicators ..... 433 Carbonel, P., Moyes, J., and Peypouquet, J-P., Utilisa- tion des ostracodes pour la Mise en evidence et L’Evolution dune Lagune Holocene a L’Ouest de La Gironde, Golte'de(Giseayis seestaen. bis sons ioeel 445 Hazel, J. E., Ostracode biofacies in the Cape Hatteras, iNorthiCarolinar areao.; Suro lan Date cos erpeer mae | k 463 Keyser, D., Ostracodes of the mangroves of South Flori- das,thein ecolopy, and, biolocy iris: Bocraet. fanvieninel 489 Whatley, R. C. and Moguilevsky, A., The family Lepto- EvyENeLdde il NTPC CMa, WatOlS oe. con gee 501 sb CONTENTS V. Microscopic structures of the Ostracoda carapace Bate, R. H. and East, B. A., The ultrastructure of the ostracode (Crustacea) imterument... 2). eee eee Oertli, H. J., The conservation of ostracode tests — ob- servations made under the scanning electron micro- SCOPE Src ce Skis er ttn GRRE cee ee Cadot, H. M., Kaesler, R. L., and van Schmus, W. R., Application of the electron microprobe analyzer to the study ofthe ostiacode carapace ..5.+-- 5 ae Schulz, K., The chitinuous skeleton and its bearing on taxonomy and biology of ostracodes ................ Swain, F. M. and Kraft, J. C., Biofacies and microstruc- ture of Holocene Ostracoda from tidal bays of Dela- WAC pe. kere. Jott tee) Gee ok VI. Classification and nomenclature of Ostracoda McKenzie, K. G. and Kaesler, R. L., An introduction to the numerical phylogeny and classification of para- doxostomatid Ostracoda, including a redescription of Machaerina tenussima (Norman, 1869) ............ MORPHOLOGIC STABILITY IN OSTRACODA Ricuarp H. Benson Smithsonian Institution ABSTRACT The carapace of the ostracode is an important functioning part of its anatomy. Specialized through time, the carapace encapsulates and protects the animal’s more vulnerable organs from predators and from crushing by move- ment in the substrate, and it adds weight to improve the animal’s benthic posi- tional stability. Several different structural “solutions” to the problem of maintaining armor, wall strength, and ballast have been employed through modification of fundamental shell construction patterns. From an engineering viewpoint the study of “ornamentation” and carapace form suggests that better design is often substituted for shell-wall material as thicker walls are replaced by more complicated systems of ribbing, reticulation, and the evolution of a more efficient structural system. Structural “failure” can be detected in some early stages of wall construction. Alignment of mass takes place within the basic working elements and surfaces in the direction of stress. In animals living in deeper water where economy of shell material is important, non- working mass is removed to lighten the shell structure. Following the distribu- tion of various modern taxa from regions of high to low levels of mechanical and thermal energy shows morphologic change commensurate with the prin- ciples of good engineering design. LA STABILITE MORPHOLOGIQUE DANS LES OSTRACODA Ricuarp H. BENsoNn RESUME Le carapace de |]’ostracode est une importante partie fonctionnante de son anatomie. Spécialisé a travers les années, le carapace encapsule et défend les organes de l’animal les plus vulnérables, des prédateurs et de la possibilité de l’écrasement par du mouvement dans le substratum, lui ajoutant en méme temps du poids, pour ainsi améliorer Ja stabilité Benthique positionnelle de animal. Plusieures “solutions” structurales variées au probléme du maintien de l’armature, la force du mur, et du lest, ont été employées 4 travers la modifications des models fondamentaux pour la construction des conches. D’un point de vue technique, |’étude de “l’ornamentation” et la forme du carapace suggére qu’un meilleur dessein se substitue souvent au matériel du mur de la conche, lorsque les murs plus épaisses sont remplacés par de plus compliqués systemes d’ossature et de réticulation, et |’évolution plus avancée d’un systéme structural plus éficace. Des ‘“échecs” structuraux peuvent étre constatés dans quelques étapes primitives de la construction du mur. Un allignement de la masse a lieu dans les éléments fonctionnants fonciers, ainsi que dans les sur- faces, vers la direction de la pression. Chez des animaux qui habitent dans de |’eau plus profond, ot |’économie dans le matériel de la conche est importante, toute masse non-fonctionnante est éliminée pour rendre la_ structure plus légére. Un examen de la distribution de plusieurs taxa modernes, qui vont d’un haut nivau d’énergie méchanique et thermale 4 un nivau bas d’énergie, montre du changement morphologique qui est d’accord avec les principes de la bonne technique d’ingénieur. INTRODUCTION Paper was expensive in ancient Egypt. It was used only for very important state and religious records. The common, everyday communication of instruc- 14 R. H. Benson tions or tabulations of construction and commerce were written on smooth fragments of broken pottery. Later, these were referred to by Greek scholars as ostracons. Today these ostracons serve as important bits of evidence in reconstructing the functions and history of this ancient culture. The tenure of the Ostracoda is about 10° times longer than the oldest Egyptian construction or the notations of the ancient engineers and tradesmen. And yet there are corollaries in the application of principles of the science of statics that prophesied the ability of the pyramids to withstand the test of time, and understanding of these same principles of structural reaction that permitted the continuance and repetition of some kinds of ostracode carapace form. In fact the ostracodes probably have employed more sophisticated design principles than did the ancient Egyptians. Students of the history of ostracodes are not used to thinking of carapace morphology as functional working structure; certainly not in the engineering sense of forces reacting within a static frame. The present study continues to explore (Benson, 1970; Benson, in press) some of the philosophical concepts and mechanical principles that may explain how this morphology can succeed under differing environmental loads and pressures. The view that stability in form has special significance will be examined from several different direc- tions: structurally, to some extent genetically, and as subsets of changing form relative to a comparative steady state reference system. Several approximations of morphologic shape as geometric form are realized and shown to be ex- plainable in terms of stress models. ACKNOWLEDGMENTS Appreciation is expressed to Alan H. Cheetham, Joseph E. Hazel, and Ronald E. Schaeffer for their valuable comments regarding this study, and to Laurie J. Brennan, Marie J. Ladd, and Larry Isham for their help in pre- paring the report. The study was supported in part by a grant from the Smithsonian Research Foundation. OSTRACODE BIVALVEDNESS, FORM AND STRUCTURE The ancestors of the ostracodes were encased in a skeleton consisting of an articulated system of thin tubes capable of responding to external stress by reaction at joints and through flexure or bending in its tough wall struc- ture. The ostracodes developed a heavier, rigid, uniformly stressed and static system of unyielding protective armor that could encapsulate the whole animal when necessary. This enveloping, bivalved shell remained an effective solu- tion to survival for the Ostracoda through a multitude of structural experi- ments under many kinds of environmental conditions. In fact this solution may have been too effective as no other arthropod group is known to have evolved from the Ostracoda. In the past, before it was convenient to examine details of carapace morphology, differences in overall shape were often described after analogous organ shapes borrowed from experience outside of the study of arthropods, using terms like mucronate, almond-shaped, or reniform. Surface texture was MorPHOLOGIC STABILITY IN OSTRACODA 15 thought to be independent of shell structure and was simply characterized in general terms such as spinose, reticulate, even rough or smooth. It is difficult to use these terms to define functional adaptive reactions. They are often conceptually sterile, or even perhaps misleading. Many are certainly not ade- quate as neutral descriptors. In any event, attempts to synthesize general architectural responses to environmental change using these concepts were not successful. Elofson’s (1941) admirable effort to relate carapace roughness or smoothness to increasing depth can now be shown to be erroneous (Text-fig. 1). Only with the development of the scanning electron microscope has it been possible to see enough carapace detail to begin to understand ornament. The present use of mechanical explanation of carapace function makes assumptions about the need for structural success in carapace form. The term “form” is used here in the sense of a conceptual model of morphologic shape, reduced to its basic system of descriptive components (in the sense of kine- matics), without reference to its structural properties of size, strength or materials (kinetics with force relationships implied). Structures respond to mechanical principles of transmission of force and are employed by carapace form primarily for the purpose of resisting environmental pressures that would bring about injurious changes in morphology. The usefulness of the distinction between the concepts of form and structure will become more evident as the discussion progresses. ESTIMATING STABILITY IN FORM In studies of ostracode allometry, it is customary to use a measure of size (length and height, sometimes width) which tends to vary in a rectilinear series with molting, and can also be found to some degree among adults along an environmental gradient (Text-figs. 11, 12, 13). These measures are not very accurate estimates of shape, even though a bivariant plot of a growth series strongly suggests stability in overall form. One must remember that size and form are independent parameters. The models of form implicit in bivariant plots of length-height ratios are rectangles. Inherent within the assumption of a mathematics based on a Cartesian system is a problem of fit that occurs between this system and one based on differential growth of surface areas. D’Arcy Thompson’s (1961) de- formations are based on changes in rectilinear distance even though the reference grid may become curvilinear (1.¢e., the x or y transformations dis- tance change would still be Cartesian). Any description of change in form is one of change in the locations of established homologous points relative to a more conservatively changing or fixed reference system. D’Arcy Thompson used curvilinear grids (Diirer transformations) referred to an initial Cartesian grid for visual but not quantitative comparisons. Implicit within this technique, however, is the lack of change of relative distance measures. As the transformations of the grids occur the reference coordinates remain the same. What is actual instability of shape remains as stability in measured form. It is obvious that the geometry of organic form is not based on a system 16 R. H. BENson 100 200 300 400 500 600 700 800 900 1000 Tn Meters Depth 2000 3000 4000 5000 6000 40% 50% 60% 70% 80% 90% 100% Relative Percentage of Rough versus Smooth Specimens in Samples Text-figure 1. The distribution with increasing depth of rough and smooth ostracodes found in about 100 samples from various parts of the world chosen at random. The data refute the hypothesis formerly held by Elofson (1941) and Van Morkhoven (1962) that smooth species compared to rough species become proportionately more numerous with depth. of right angles (sometimes called the urban angle system). The basic geometry of morphologic form and that of the mechanical model should be congruent. I am not confident that a disparity between these analytic systems and that of the essential geometry of the skeletal system may obscure more than is re- vealed. Therefore, I would like to explore another way of model construction based on effective cause, i.e., functional as opposed to descriptive allometry. The pattern of distribution of pore conuli, the pattern of the reticulum (Benson, 1970), a model of the interaction of the major structural ridges and surfaces of the carapace; all of these simplifications of structural systems repre- sent different but related functional levels of reaction (stress response) in- cluded in the carapace. These systems do not all react through selection to MorPHOLOGIC STABILITY IN OSTRACODA 17 eee * e @ ®@06060 86 b Text-figure 2. Two patterns of spine and pore conuli distribution in (a) deep-sea, very spinose species related to “Cythere” acanthoderma Brady, 1880, and in (b) a shallower, less spinose species related to “Cythere” scutigera Brady, 1868 (see Text-figure 12). The principal spines and their pores are homologous with those found in reticulate species which are otherwise different in general shape and sculpture. environmental stress at the same rate, however. The distributionat pattern ot receptors of the tactile nervous system (possibly expressed in the setae extending from the pore conuli distribution) seems adequate for many ostracodes with very different shell sculpture. The dermal tissue pattern of shell-forming cells (shown in the reticular pattern) seems to be present in heavily murate ostra- codes and ones with no ridges at all. These systems may be genetically more conservative, their form or intrinsic geometric pattern of distribution more stable than that of the mechanically more reactant skeletal system. Also with growth the requirement for skeletal mass is a function of volume change and tends to increase exponentially at a faster rate than that of the tactile surface, which is a function of change in area. If the tactile surface area remains con- stant between strong and weak forms the pore conular pattern might remain static while the structural configurations could vary radically. Therefore, assuming adaptive response varies among functional systems 18 R. H. Benson according to their sensitivity to selective pressures, and that skeletal response is primarily mechanical reaction to preserve the forms of the other systems, a hierarchy of inertial relationships (expressing resistance or immunity to change) can be recognized. This hierarchy of changing patterns also expresses a series of sets of geometric form whose proportions vary at different rates and whose changes can be described relative one to the other. In celestial mechanics, which deals with relative motion within and among star and planetary systems, the reference system used for description is that of the constellar network of the positions of the so-called “fixed stars”. This primary inertial system serves as the foundation of the reference coordinate system for the description of relative celestial motion. If such a primary inertial system can be found among homologous points in ostracode carapace morphology (Text-figures 2-3), a basic natural coordinate system could be established for description of relative deformation among related organic forms. If skeletal form is a natural diagram of forces, as D’Arcy Thompson (1961) has sug- gested, the departure from or tendency toward structural stability, expressed as substitution among structural members within a system of changing work capacity, may be the best way to describe relative change and functional adaptation (Text-fig. 4). The reordering of the system under different loads can be best visualized by reducing a succession of stages of substitution to the same reference base. When relative mechanical stress increases (independent of size), the number of skeletal elements is reduced departing from the basic, commonly held pattern of reticulation. I began exploration of this principle earlier with the study of Agreno- cythere and some related forms (Benson, 1972), in which the pore conuli ap- pear to be the most consistently arranged of the carapace features examined. Constellar networks, connecting named and identified pore conuli, were constructed in this work and shown to vary among some 16 sexually and taxonomically distinct forms. This network seems to be the primary inertial system of reference for a very large group of ostracodes. In the present work the same basic system of reference is refined and extended to the Bradleyinae (Text-figs. 4-5). Elements within the patterns of fossae and reticulation change at more accelerated rates. It is possible to define relationships among forms whose reticular patterns may be dominated by the emphasis or the replace- ment of certain murae by following the fission or fusion among the fossae. STRUCTURAL STABILITY To an engineer the concept of structure refers to the organization of form responsive to physical properties for its continuance against those forces that would alter it. Structure also helps to define form in efficient and logically consistent physical terms. A structural system is an ordered assemblage of structural elements that physically react in concert depending on the properties of the materials of which they are constructed. The biologic concept of organ and that of structure are compatible. The same js true of certain relationships between mechanics and geometry or proportionate relationships set in mathe- matical space, consequently mechanics can often be reduced to mathematical MorPHOLOGIC STABILITY IN OSTRACODA 19 terms. Mechanical determinism and morphological stability may therefore be related. Stability, strength and economy, are the principal functional requirements of most skeletal structures. These properties of skeletal systems are often as- sumed by the morphologist. The animal exists and obviously was selected as structurally more successful. However, explaining how one form potentially reacts or reacted (in extinct species) requires a hypothesis of force. This Newtonian position is not an easy one for the biologist. There is an extensive literature on the limits of the mechanistic philosophy (Russell, 1916; Beckner, 1959; Bertalanffy, 1962) which will not be debated here; however, it does seem possible to stipulate that skeleton systems do exhibit stress reactions g & > rae i, Cae ae Pe ce Text-figure 3. A schematic diagram or constellar map of the relative distribution of the normal pore canals and pore conuli which constitute a primary inertial system for reference in studying relative change in other aspects of the ostracode carapace sculpture (see text and Benson, 1972). R. H. Benson 20 ‘aBINUI DAISSEU a10UI Aq pajyeIEdas AESSOF IaM|F YIM SAUO II|[BWS MO][EYS ay} pue xa[dulod a1oUl SABM]e BUIaq ‘sauo Jadaap ay} YIM SUIIOJ asay} JO [[e YsNo1Y} pa0eI} r eo ee ce) on. << 0 a Depth in Meters Text-figure 11. Increase in average size (in mm) with depth of species of Bradleya. 30 R. H. Benson Spinosity is a special structural attribute. It has great functional impor- tance but is not either statically determinate or geometrically stable. Spinose ostracodes usually become larger and more spinose with depth (Text-fig. 12). However, as Echinocythereis becomes larger, it does not necessarily acquire more spines (Text-figure 13). The function of spines is presumed to be de- fensive to ward off predators or to extend sensory setae. The relative length of the spines does not seem to correlate directly with changes in depth as does their number. The positions of the major spines are not random but appear to be genetically fixed (Text-fig. 2). Some shallow forms have very long spines. These species must live in quiet water, as is true of deep-sea species, to prevent breakage of the spines. An increase in spinosity with depth may be the result of an increase of potential predator selection over mechanical selection, but this is speculation. Other classes might include compound tetrahedronal forms (Text-fig. 14) or compound spherical forms (Text-fig. 7). These simplest geometric shapes, often found in joined sets, tend to reinforce one another as parts of another architectural type or becoming dominant on their own. All of these structural morphotypes intergrade with one other. It is con- ceivable that a large ostracode taxon may find stable structural solutions in all of these types. STRUCTURAL MECHANICS The structural problem of the ostracode carapace is to be able to encapsu- late the animal beyond its distal-most, softer regions, and yet remain divided into two parts for appendage extension and general access. A single valve must economically, yet with strength, span a broad space. Much of this space may remain unoccupied by any compressive, body-fluid support. The most economical space-enclosing structure for spanning a considerable distance with the least mass is a dome, that is a three-dimensional structural derivative of the catenary arch (Text-figs. 15-16), having the capacity to react latitudinally as well as in the planes of the arch-shaped meridian sections. To enclose a maximum volume with the minimum surface, the sphere is most efficient. However, when it is divided, the margins of the sphere are weakened and subject to bending; and when it sits on a support, the stress of a sphere is not uniform. A hemisphere is not strong compared to a domal system with catenary arch sections. A catenary arch is strongest to resist force normal to its crown and uniformly distributed along its span. A horizontal force, oblique to the crown of an arch or against its side, would have to be transmitted un- equally through the crown and down the other side producing high bending moments. A dome however, transmits the oblique forces through latitudinal resistance causing rapid dampening of the bending. For benthic ostracode species the domes of the valves must be modified to form a strong union along the hinge, provide ventral stability, and support the free margins against bending and unresolved thrust. The elongate dome, modified vault structure, and shell-frame all are used to satisfy these require- ments. These are the most common structures in benthic ostracodes. Their Length X Height MorPHOLOGIC STABILITY IN OSTRACODA ou INCREASING SPINOSITY 3 D 0 aw © e@@eeee@#ee QO OGmmacnoncno cok 100 200 300 500 1000 2000 39000 Depth in Meters Text-figure 12. Increase in average size (in mm) and spinosity with depth of end members of a series of trachyleberid species including “Cythere” Scutigera Brady, 1868, and “Cythere”’ acanthoderma Brady, 1880. 32 R. H. Benson efficient cross-section approaches some portion of a catenary arch, depending on the orientation and the interference of other structures (Text-fig. 17). Un- derstanding the structural properties of the catenary arch suffices, at least as an introduction to structures that obviously become more complicated as they are combined in actual carapaces. The major structural problem posed by the catenary arch, or the dome forming the valve of the ostracode, is the resolution of the thrust that causes bending near the free margin. This may be of considerable magnitude in forms of low rise relative to the span. Because it is not practical to join the margins with cross tension resisting members, a tension ring must be employed. It should be remembered that the calcite composing the shell has considerable compressive, but little tensile strength. So that either calcite mass or chitin, DIMINISHING SIZE OF EYE TUBERCULES . = . a ; : o : . ‘ i »< : <= 7 ° ie i o s _ , 3 Ct if H 3 2 3 ° gS C 3s . = ett o zie ° q Tee c Cate = ewe <= : uw z 4 300 500 1000 3000 5000 Depth in Meters Text-figure 13. Increase in average size (in mm) with depth of species of Echinocythereis. Other changes include thinner, less massive spines (also fewer), and the gradual attrification of the eyes (inferred) and reduction of eye tubercles with depth. MorPHOLOGIC STABILITY IN OsTRACODA 33 Text-fig. 14. The compound tetrahedroid shape contained within Caudites. A tetrahedron is the most direct solution to the problem of reaction of a space enclosure of compression inducing loads received along a line. This compound structure could conceivably be very strong to resist impact from several directions from objects much larger than the carapace itself, or it could also support its shape with a very thin wall. 34 R. H. Benson Text-figure 15. The principle of the catenary. A chain or cable has great capacity to span long distances because it assumes the form of stress equilibrium plus placing a considerable reaction moment between the realized line of inward thrust at the points of attachment and the mass itself. A catenary arch is equal in compression to stress distribution to a cable under tension. The vertical load is distributed equally along the extent of mass. An unloaded arch with a uniform radius diverges in form from the catenary and is not in static equilibrium unless the wall thickness and strength is sufficient to pro- vide sufficient reaction moment. MorPHOLOGIC STABILITY IN OsTRACODA 35 which has tensile but not compressive strength, must be added near the margin to resist a high bending moment. Close examination of the shell margin (Text- fig. 18) at the infold shows that the calcite laths (the parallel layers of calcite crystals — like bricks) of the shell wall continue across the so-called zone of fusion, mistakenly thought in past to unite the “inner” and “outer” lamella. Strength is continued through a change of direction and shape, plus the addi- tion of mass, usually with only minor alterations in composition. In very thin monocoque shells, the possibility of bending caused by the thrust of the catenary form is increased, and accessory stiffening structures or a considerable increase in mass may be required to maintain the shape and prevent buckling (Text-fig. 16). There are several solutions to prevent bending and to absorb or redirect the thrust, within the shell and infold, or on the outside of the shell (Text-figs. 19-20). These outside structures, which stiffen and strengthen the margins, may eliminate the primary strength purpose of the infold, and this function of the infold may become vestigial (fused). The principle of the catenary can be seen well exhibited in fresh-water monocoque shelled ostracodes (Text-fig. 21), where the infold is best developed and auxiliary external shell structures are fewest. SOURCES OF STRESS The forces that are capable of producing strain, deformation, and failure in the ostracode carapace are both internal and external to the shell (not to be confused with the forces in the shell wall itself). The internal forces originate principally from the support of the non-skeletal inner organs, the appendages, reproductive organs and their activity, and especially from the closing adductor muscles. The sources of external forces are less obvious. These involve those resulting from the position and movement of the animal at the interface be- tween the water and the substrate and the movement of these media around the ostracode. Examination of the attachment of the adductor muscles at the so-called “sears” shows that the tensor muscle fibers penetrate into the shell to be anchored to wedge-shaped calcite prisms. The prisms are similar to key- stones in an arch. They are clustered and extend to the outside surface of the shell. Their outer surface is larger than the inner, resulting in an effective structure to prevent shear that could occur with the force being concentrated normal to the shell. Often there are local compensating structures on the outside of the shell such as the “bridge” in the bradleyids, the muscle-scar node in the trachyleberids, and the circular castral structure as in Agrenocythere. The presence of external forces should be implicit in the apparent strength of the shells. The valves are often far stronger than is necessary to support their own weight or to react to the forces originating with the closing muscles. Controlled breakage of the valves under the microscope, in order to examine their inner structure, requires considerable force. In spite of the absence of observational data, it must be assumed that protection against crushing or im- pact force is the foremost reason for a massive, stronger shell. For those ostra- codes living in the upper zone of actively moving or agitated substrate, the 36 R. H. Benson b Funiculer surface of equilibrium ~ outer lamella | | Text-figure 16. Solutions to problems of spanning great distances with the least possible mass under compression. Considerable lateral thrust is de- veloped which may be expressed as bending or which must be absorbed either in the supports or in a reaction element under equal and opposite tension. In a dome the bending may be absorbed in the latitudinal “hoop” forces developed around its axis. A section through the marginal region of the thin shelled ostracode Cypretta shows how the curvature near the edge departs from the surface of equilibrium and stiffeners are required to translate the thrust from the outer lamella into the infold forming the reacting tension ring. MoRPHOLOGIC STABILITY IN OsTRACODA 37 shell walls must be reinforced especially against impact from above. For those ostracodes that live on the surface of fine, stable, yet soft substrate, the venter is extended and the dorsal lateral] walls may require less strength. THE ROLE OF ECONOMY IN DESIGN The carapace of the podocopid ostracode encapsulates the animal in pro- tective armor at a considerable metabolic expense. Not once, but as many as nine times, the animal doubles its size secreting a rigid skeletal mass nearly equal to the volume of its own body fluids. With the possible exception of the barnacle, which is sessile, no other arthropod expends as much energy for the purpose of developing a protective cover or skeletal support. It must be as- sumed that no more mass is created than is necessary for the potential require- ments of strength and positional stability. Other mobile invertebrates secrete or excrete rigid skeletal frames that are proportionally equal to or greater than the relative mass of the ostracode, but these are built gradually by accretion over the life span of the individual. Those that build by continued addition save mass, but suffer the problem of adding efficient structures to existent frames built to carry less load. The ostracode must generate a series of increasingly larger and consequently lighter working designs which are significantly modified each time it inflates the non- rigid membranous patterns to which supporting, compression resistant mass is then added. The difference between these two systems is not only long term economy, but also the vulnerability of the structure of the ostracode as a static frame at the time of ecdysis. The arrangement of structure of the ostracode carapace is probably more efficient and flexible in design than other bivalves, although more costly in constructional metabolic energy. Text-figure 17. Serial sections through a relatively simple species of trachyleberid shallow-water ostracode from Madagascar showing the coinci- dence of the catenary form through the shell between major structural mem- bers. In the anterior, where the shell is nearly unsculptured, the catenary form and the whole span are identical. Passing to the posterior the ventrolateral ridge appears in a plane normal to those of the sections causing interference, division, and the reversal of the catenaries. The arrows show the vertical axis of the catenaries of which only a section is represented (drawn from actual chains in suspension). ‘uoIdaI SITY} UT SUOTJDaS Uayo1g Jo sydeiso19IWI -ojoyd Uor}9a;9 Suruuess Aq paulityuod st pue JasuoIjs A[snorAqo st 19k] AT, ‘uoneredas OU YUM Pplojul Ue se e[[auie, 13}No0 9Y} Fo AJINUTZUOD JY} SurMoys (q) day3}0 ay ‘(TS6T “Surjsay 1a3fe) 2dUadsaIIU0D Jo aUOZ B Suoje e[jswe] Jajno puke JauuUrT ay} Jo Uorsny Ay} YIM [apow Ie[jawelIq ay} Burmoys (ev) auCO ‘][2YS epooesjso ay} JO UIdIeW ay} JO SUOTJEJIIdI|JUT OM], “BT IINBIZ-3x9 J, aanyonays [pays y}ye] Ssnonulzuoy joup2 aiod jp!ppi R. H. Benson o Do) Le} > o POs4I ax CZ eee &f WAY sits aanzINsys [JAYS Ye] SNonulzuOIsiGg auoz poulSinw aouaosaiouod saiod |D1ia4,D] 10 saiod ;pwioUu aBpajas D||]@wo}; seuu) jo ys4pd paly!ojp9 s|[@2 ;owsapidea pub ;DWJapqns wNligi|inba 4o aoDjins sDjND1UNY MorPHOLOGIC STABILITY IN OsTRACODA 39 Text-figures 19 and 20. Conditions of a dome showing the problem of thrust and several solutions similar to those found in ostracodes. These models are made on the assumption that the material used has much less tensile strength than compressive strength. 40 R. H. Benson Text-figure 21. Longitudinal and saggital sections of Potamocypris? steueri Klie, 1935 (taken from Gauthier, 1939) showing a comparison between the catenary form of a spanning chain in tensional stress equilibrium (the equal and opposite of compressional span stress equilibrium) and the longitudinal shape of the carapace. The lower illustration of the chain and section together is an actual high contrast photograph of the experiment. The fit is better than 90 percent with the ends departing from the catenary form, presumably under the influence of local increased thickness to resist bending near the edge and the presence of the infold (duplicature sensu lato). MorPHOLOGIC STABILITY IN OSTRACODA 41 As a general working premise, it seems reasonable to assume that an ostracode, regardless of its size or structure, does not build a stronger or heavier carapace than is likely to be required during its lifetime, based on the adaptive experience and success of its predecessors. The variability of design becomes consequently restricted by genetic factors. Environmental change in its many complex and often unknown or unknowable progressive or oscillatory forms is much more rapid than average genetic change within a population. Therefore, both genetic and the consequent form of structural systems react conservatively within a series of subsets of more active surrounding systems of external influences. These systems are progressively more or less inertial toward the system of skeletal frames, which is the most effective reactant against the pressures of change. Not all of the structural systems are in equilibrium with the environmental systems that brought them into being. There is a lag perpetuated genetically. This is especially evident if the structure represents a very minor metabolic taxation for its construction. Of course structures generally exist somewhere between this potential and realized functional status. If a trade in functional roles of structures is gradually brought about, such as a gradual increase in general or local shell thickness that may eliminate the need for a ponticulate compression-resisting ridge, the replaced structure diminishes and disappears. I would judge that this is happening with the dorsal ridge of Pterygocythereis jones (Baird, 1850). EVOLUTION OF STRUCTURAL TYPES Thus as a result of a hierarchy of functional responses and the presence of potentially equal series of operating mechanical reactions, there may be a definable number of architectural solutions or structural systems available as options toward the evolution of a successful carapace design. Convergence of form from among ancestral stocks with differing recombinations of struc- tural systems has been commonplace in the history of ostracodes. Arch-beam designs are present in velate beyrichaceans. There are corrugate quadrijuga- torids, box-framed kirkbyaceans, and so on. The fact that there are several ways to achieve strength besides just an increase in mass has made the diversity of ostracode form, as we know it, possible. How are these recombinations achieved? I suggest that changes in the depth in the habitats of benthic ostracode species subjecting them to changes in mechanical to predator selection pressures may be responsible. This is to say that when either of these pressures is great and predictable, the morpho- logic variability as well as the geometric complexity of the design decreases. The morphologic choices are locked in as structural responses. With relaxation of these pressures, the inherent morphologic patterns of the carapace, those that control the basic pore and reticular patterns and tend to be temporarily geometrically more complex, reassert themselves. These more complex, perhaps mixed, structures, while weaker to resist mechanical pressures, provide the “roughness”, or pseudospinosity necessary to ward off predators. Where 42 R. H. Benson severe predation, such as occurs in deep-sea cropping, defensive structures such as spinosity, become extremely exaggerated. If almost no stress is present, or if it tends to be uniform, the smooth thin shell would result leaving only the traces of the basic carapace patterns. As the “complex” forms reinvade regions of high selection pressure they may not reappear in the same structural mode as before. Variation in Bradleya in geographically isolated shallow shelves tends to follow this differential structural selection. Morphologic stability therefore tends to occur in two regions; that which represents a relatively simple but locked-in structural solution under continual mechanical, thermal or chemical (salinity change) selective pressure, and that which seems to occur in very stable physical conditions like the deep-sea where predator selection pressure and metabolic restrictions on shell con- 50 100 150 200 250 300 350 400 Number of Specimens Text-figure 22. Relative species diversity among samples collected from the deep-sea (depths greater than 1000 meters; dots) and samples collected on the shelf (depths generally between 10 and 200 meters). Fossil samples of the same depths are also indicated (squares) with the ages shown (K, Creta- ceous; E, Eocene; M. Miocene; P, Pliocene). The species diversity (S-s is total species minus species with only one specimen found in a sample) of deep-sea psychrospheric faunas seems to have remained about half of that of temperate shelf faunas over the last 20 million years or perhaps longer. 43 MorPHOLOGIC STABILITY IN OsTRACODA <00l ‘pulq 9q 0} Jdz are suonrtpuos jjays fo [eordAy asoy} UeY} 1a}vaIS syidap UI SUIAT] Satsads ay} FO J[eY ULYI 2IOJA] ‘s19}9UI YO8 OF 009 ULY) 1a}v013 syidap Ul pul[q awodaq sardeds [[e Isowpy “YyYJdap Sulsvaiour YIM (saposaqny aha YIM Sarsads 0} pajejar Ajasoja 10 sajoa1aqn} aX3 aAevy 0} UMOUY Sao) sarzads pazysIs Ajjenuajod Suowe ssoupurq aeaAnejar fo voNnqiysip ayy, “EZ aanB1yZ-3x9,7, sajdwes ul saisads |e}O, SNSABA PUI] 4O aHbey,uadiag BAI}LIIY 0) 08 o0L 009 70 0S 70 OF o0€ %0¢ 700 L e : SSINGALHOIS JO ST al ll ls oe SLIWI1 YIMOT JALVWIXOUdd VY é°? 008 QOS O000l 000¢ yydaq S4a}aWw ul 44 R. H. Benson struction are great. Brackish and littoral environments have low species diversity and long tenured taxa. This is also true of deep-sea faunas (Text-fig. 22). The middle and outer shelf seems to be the major breeding ground for new taxa. A clue to the history of invasions of the deep-sea or from deeper waters to shallower waters may be found in the presence and absence of eyes among some related species. Presumably eyes once lost cannot be regenerated. There- fore a sighted shallow species has not phyletically descended from a deep form. Contrarily, the occurrence of a sighted form, which has many related deep-sea blind species, may indicate the place of origin of this species group. A distributional study of blindness with depth is given in Text-figure 23 which may also have value for paleoecological interpretations. CONCLUSION I have purposely focused this discussion on concepts that are not generally considered by students of ostracodes. Simulation of form by mathematical modeling is not yet possible. As in other study areas, mechanical relationships are appreciated before they can be formalized. And yet the difference between our view of carapace form as descriptive and functional will be founded on principles similar to the ones discussed here. Some of these are: (1) that rela- tive change in carapace morphology is better described through a coordinate reference system implicit in the animal, and that this reference system is inertial or the most stable; (2) that the lack of change in the evolution of carapace morphology represents successful reaction to external pressures; because (3) the purpose of carapace shape or structure is to uniformly transmit stress from the environment to be protectively absorbed into the strength of shell material without causing failure in any one of its structural elements. If there are stability phases in the evolution of ostracode carapace form, these may be interrupted, not by increases in environmental pressure, but by its relaxation. The difference between an engineer and a morphologist is not as great as might be first imagined. It is the task of both to abstract the functional characteristics of structural systems with the aid of the best theory available. REFERENCES Beckner, M. 1959. The biological way of thought. Columbia Univ. Press (New York), pp. 1-200. Benson, R. H. 1970. Architectural solutions to structural stress in rigid micro-organ- isms, through SEM examination. Proc. Third Ann. Stereoscan Collog., Kent Cambridge Sci. Inc., pp. 71-77. 1972. The Bradleya problem, with description of two new psychrospheric ostracode genera, Agrenocythere and Poseidonamicus (Ostra., Crust.). Smithsonian Contr. Paleobiology 12, pp. 1-150. [In press]. The role of ornamentation in the design and function of the ostracode carapace. In Geoscience and Man, Louisiana State Univ. Press. MorPHOLOGIC STABILITY IN OsSTRACODA 45 Bertalanffy, L. von . 1962. Modern theories of development; An introduction to theoretical biology. Harper Torch Books, Harper & Brothers (New York), pp. 1-204. (Reprint and translation of the 1933 book by J. H. Woodger). Elofson, O. 1941. Zur Kenntnis der Marinen Ostracoden Swedens. Zoologiska Bidrag fran Uppsala 19, pp. 215-534. Gauthier, Henri 1939. Sur la Structure de la Coquille chez quelques Cypridopsides a furca réduite et sur la validite du genre Cyprilla (Ostracodes). Bull. Soc. Zool. France 64, pp. 204-228. Henningsmoen, Gunnar 1965. On certain features of Paleozoic ostracodes. Geol. Foreningens i Stockholm Fordhandl. 86, pp. 329-334. Kesling, R. V. 1951. The morphology of ostracod molt stages. Univ. Illinois Biological Mon. 21, pp. 1-317. Morkhoven, F. P. C. M. van 1962. Post-Paleozoic Ostracoda; their morphology, taxonomy and eco- nomic use. Elsevier Publ. Co., 1, pp. 1-204. Neale, J. 1964. Some factors inflencing the distribution of Recent British Ostra- coda, In Ostracods as ecological and paleoecological indicators. Pubbl. Stazione Zoologica di Napoli 33, pp. 247-296. Russell, E. S. 1916. Form and function. John Murray Publishers (London), pp. 1-383. Thompson, D’Arcy W. 1961. On growth and form. Cambridge Univ. Press (original 1917 edi- tion abridged and edited by J. T. Bonner), pp. 1-346. Richard H. Benson, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560. U-S.A. DISCUSSION Dr. A. Liebau: First of all, you have used only one of the two main pore systems. There are the cone pores and there are the mesh pores. The cone pores are not so valid for this compilation as are the mesh pores. There is at least one group in which the cone pores are useful, that is the Acanthocytheris group. But the mesh pores have only undergone reduction in the Trachyle- berididae. You will not find a species with more than 140 mesh pores, and that only in the oldest ones. From that point onward only a reduction in mesh pores is to be observed. New mesh pores are not developed. Dr. Benson: I agree with some of what you say. As far as my own observations are concerned the problem is that the mesh pores are not always so easy to find. To identify these in some of the smoother animals is very difficult. Of course there are changes in the pore conulae, there are new ones I’m sure, but it is easier to work with 20 pore conulae than it is 140 of the mesh pores. Dr. A. Liebau: Well one remark should be confirmed if we compare two genera of Pokorny, but I should not mention Pokorny because he cannot be here. It is too bad that Dr. Pokorny cannot be here, as he would give a good lecture on this subject. It would be very interesting to see what he would say to this lecture. 46 R. H. Benson Dr. Benson: As you know Professor Pokorny spent a year with me in 1967. Some of the ideas that I have shown here originated from that time. We discussed much of this at that time, in fact some of the diagrams that you saw were drawn then. Dr. H. Uffenorde: Do the specimens, on which your correlaticn between size of carapace and depth is based, come from sediments with the same physical properties? Dr. Benson: No attempt has been made to correlate changes in sediment properties with the increase in carapace size. It is my impression that in general the smaller sizes are associated with shelf clastic sediments and the larger sizes with pelagic sediments. Dr. H. Uffenorde: Did you get any data concerning the degree of exposure to light from the microenvironments from which your ostracode species, showing a reduction of eye tubercles, come? Dr. Benson: Only that available from the literature. Dr. H. Puri: I think we should commend Dr. Benson for an excellent study. He has tried to relate ostracode structure to known engineering principles. I think most of the work he has done has been with the trachyleberids, and I would like for him to continue this and study the polycopids. Dr. Benson: Thank you Harbans, I am very interested in Polycope because it seems to approach one of the simplest engineering solutions. However, I am not very well informed about its taxonomy. Dr. H. Loffler: If I understood you correctly, you studied the mechanical stability of ostracode shells. I wonder whether you have taken into account that the animal in water has specific weight of between 1 and 1.5 so that if you compare this with the Roman arches the latter increase proportionately to give a thickness of 160 to 200 meters. There is such a bend in the shell anyway that I don’t really believe it is necessary to explain its strength in terms of mechanical principles. You can notice the same thing with plant seeds and so forth. This structure is known only to follow evolutionary trends, with relation to selection and other things, without requiring an explanation in terms of mechanical principles. Dr. Benson: You’re implying the effect of gravity as the basic efficient cause and I did not intend to do that. I’m talking primarily about potential impact, and potential impact implies mechanical instability of the substrate and the crushing capability of predators. I do recognize the importance of mass as it increases the sinking factor however. As to the matter of relative thickness, I might also interject that your analogy of the Roman Arch, if you will study new engineering designs of pre-stressed concrete, you'll find that it is possible to span the English Channel with that much concrete, and still follow the basic principles of catenary suspension. The principles of distribution of stress apply no matter what scale it is, or in what medium. I would add that in thinner shells I think the adductor muscles are the principle source of the stress. REMARQUES SUR LA DIVERSIFICATION MORPHOLOGIQUE DE TROIS NOUVELLES ESPECES D’ELPIDIUM (OSTRACODA) A CUBA Dan L. DANIELOPOL Limnologisches Institut, Wien, Austria RESUME Le genre Elpidium F. Mill. était connu jusqu’a présent, par une seule espéce, E. bromeliarum F. Mill., vivant dans les coupes des Broméliacés de l’Amerique du Sud et l’Amerique Centrale. En étudiant plusieures populations d’Elpidium, des Bromeliacés de Cuba, l’auteur a decouvert trois nouvelles espéces: Elpidium n. sp. A, Elpidium na. sp. B et Elpidium n. sp. C. Dans Il’une des localitées cubaines, Elpidium n. sp. A et Elpidium n. sp. C. vivent ensemble. Trés probablement, il y a un isolement sexuel entre ces deux espéces, comme on n’a pas trouvé de formes hybrides. Les nouvelles espéces d’Elpidium différent par les détails de l’organe copulateur male et des valves. On décrit briévement l’organe copulateur m4le et les caractéres sexuels secondaires des Elpidium de Cuba. On remarque que les plus importantes différences entre ces trois espéces sont données par les lobes génitaux de l’organe copulateur male qui trés probablement jouent un role sensoriel. A |’avis de |’auteur se sont ces appendices a fonction sensorielle que assurent dans une grande mesure, l’isolement sexuel. L’étude comparative des valves des nouvelles espéces d’Elpidium de Cuba révéle des différences morphologiques significatives. En s’etayant aussi sur d’autres exemples |l’auteur attire |’atention que l’examination attentive de l’organe copulateur male des Ostracodes est absolu- ment nécessaire, étant donné que cet organe assure |’intégrité de |]’espéce par l’intermediaire du processus de |’isolement sexuel. En général, les différences morpholgiques interspécifiques de l’organe copulateur male sont couplées aussi avec des différences morphologiques des valves. Cette derniére remarque peut avoir quelque intérét pour le palé- ontologiste. REMARKS ON THE MORPHOLOGICAL DIVERSIFICATION OF THREE NEW SPECIES OF ELPIDIUM (OSTRACODA) FROM CUBA ABSTRACT The genus Elfidium F. Mill., is known by a single species, E. bromeliarum F. Miull., living in the bromeliads cups from South America and Central America. Studying several Elpidium populations from the bromeliads of Cuba Islands, the author discovered three new species: Elpidium, n. sp. A, Elpidium, n. sp. B, Elpidium, n. sp. C. In one of the cuban localities, Elpidium, n. sp. A and Elpidium, n. sp. C live together. Most probably there is a sexual isolation between these two species, as no hybrids were found. The new Elpidium species differ both by the male copulatory organ and the valve details. 48 Dan L. DaANIELPOL The male copulatory organ and the secondary sexual characters of the Cuban Elpidium are briefly described. It is noticed that the most important differences between these three species are the details of the genital lobes of the male copulatory organ which probably display a sensorial role. In the author’s opinion these limbs having a sensorial role insure, to a large extent, the sexual isolation. The comparative study of the valves of the new Elpidium species from Cuba Islands, shows significant morphological differences. Based on other examples, the author believes that it is absolutely necessary to make a careful examination of the ostracod male copulatory organ as their peculiarities insure the integrity of the species by the intermediary of the sexual jsolation process. Generally, the interspecific morphological differences of the male copula- tory organ are connected with morphological differences of the valves. This last remark can be of some interest for the paleontologist. INTRODUCTION Il y a presque cent ans (1880), F. Miller décrivait au Brésil un ostracode remarquable, Elpidium bromeliarum, nouveau genre, nouvelle espéce, qu'il avait trouvé dans les coupes des broméliacés, plantes épiphytes des palmiers. Récemment Pinto et Purper (1970) ont effectué la révision du genre Elpidi- um, arrivant a la conclusion qu’a l’intérieur de ce genre on peut reconnaitre, pour le moment, une seule espéce, E. bromeliarum, F. Miller. D’aprés les auteurs brésiliens cités, le genre Elpidium est répandu au Brésil, au Costa Rica et a la Jamaique. Les recherches que Monsieur le Professeur Tr. Orghidan (Bucarest) et Monsieur N. Vina (La Havane) ont effectuées en 1970 a Cuba sur les coupes des broméliacés de la région Santiago-Baracoa, ont permis la mise en évidence d’une riche faune d’Elpidium représentée par trois nouvelles espéces que je nommerai £., n. sp. A, E., na sps Bb. et, sp. iC. Je rappellerai que les coupes de broméliacés sont des petites cuvettes formées par les feuilles de cette plante épiphyte qui se remplissent d’eau et de détritus et ou s’installe une riche faune. Ces microbiotopes aquatiques sont perchés a plusieurs métres de hauteur sur les palmiers; en conséquence, la dispersion de ]a faune ne peut avoir lieu que passivement. Parmi les trois espéces d’E/pidium cubains, E., n. sp. A a une répartition vaste étant donné qu’elle a été trouvée sur la Gran Piedra et dans la vallée de Rio Indio (prés de Santiago de Cuba), sur le Rio Sabanilla (prés de Baracoa), dans la localité Yumuri (sur la route qui méne a Sabanilla). E., n. sp. C a été récolté dans la vallée de Rio Indio, dans la méme station que £., n. sp. A; en- fin, E., n. sp. C a été trouvé prés de Siboney a une douzaine de kilométres de Rio Indio (Text-fig. 1). Le fait que les stations de deux des nouvelles espéces sont trés proches l’une de l’autre et que deux des nouvelles espéces ont été trouvées dans la méme station pose le probléme de |’isolement sexuel comme facteur important pour le maintien de |’intégrité de l’espéce. La question de |’isolement sexuel chez des espéces d’ostracodes proches du point de vue morphologique avait déja attiré mon attention 4 l’occasion de l'étude des Candona du groupe neglectoida (Danielopol, 1969). Dans le cas 49 DIVERSIFICATION MORPHOLOGIQUE E.pripi1um CuBa *(Aauoqig *¢ evoovieg “p 1inWINX ‘¢ OIpuy org ‘% BIpatd UkIH “[) aUaIIQ UoId21 Be] SuEp BeqnD e& (¥) CO ‘ds ‘u “7 12 (@) gq ‘ds ‘u “7 ‘(e) y ‘ds ‘u ‘wnipid)y,p anbrydess093 uonseday “Tf |B1j-3x9,7, le +14 50 Dan L. DANIELPOL des Elpidium de Cuba, comme dans le cas des Candona citées, il m’a semblé utile de rechercher quelles sont les particularités morphologiques qui pourraient assurer un isolement sexuel; d’autre part i] m’a paru intéressant de voir s’il existe une relation entre la diversification des appendices et la diversification des valves. REMERCREMENTS Monsieur le Professeur Tr. Orghidan et Monsieur N. Vina ont bien voulu me confier l’étude des ostracodes cubains; je les remercie vivement. PARTICULARITES MORPHOLOGIQUES DES ELPIDIUM DE CUBA Les trois nouvelles espéces d’Elpidium possédent quelques traits morpho- logiques communs tout a fat remarquables, qui sont probablement des carac- téres génériques: la charniére est faiblement développée, l’antennule posséde une bosse antérieure sur le premier article, l’antenne a un dimorphisme de griffes endopodiales distales ainsi qu’une chétotaxie trés spéciale (voir pour plus de détails, la figure 3). Le palpe mandibulaire posséde un poil distal bifide. L’organe copulateur male a un flagelle placé sur la face externe d’un lobe A, large, le crochet accessoire petit et fort entre le manchon placé a lextérieur de la gaine pénienne. Le complexe copulateur placé sur la face ventrale est orienté en position normale avec le lobe A vers |’avant et le manchon et le crochet du coté médial (Figure 4). Le squelette interpénien pos- sede une piéce interzygum tout a fait spéciale par rapport a ce qu’on connait chez les autres groupes de Cythéracés. Text-fig. 2. Elpidium, n. sp. A 9, valve gauche (photo prise au SEM par Fr. Saffon, §.N.P.A., Pau). (Dimensions in text.) 51 DIVERSIFICATION MORPHOLOGIQUE ELPIDIUM CUBA ‘(ayIpodoxa | ap aseq — Xaq ‘ajduns [lod — sq foseiayjsov uN & jUR[qUIassaI duTjeAy UoeUIO, — AY ‘]eIsISAaA [10d — 9a ‘soa[ejsIp sazyrid — dp ‘wy ‘e5) a31podoxay ap aeurxoid uorda1 ‘yy ‘aypodopuay np ae sip aIxejO}9YO “| “ajyur ‘auuazue | ap sjreyp “gq ‘ds ‘u “wnipid)y “A “A ‘appur “9are| -nqipuew adjed np [vysip jrod ‘q ‘aj1podoxa] ap ajeumtxoid uorde1 ‘D ‘ajem ‘g ‘ajjemiey ‘Wy ‘altpodopua | ap a[eIsIp arxejojgy9 ‘gq ‘yy ‘auuajuR], ep s[Iejlop ‘O-V ‘(eiparq ueiny ap sairejduaxs) y ‘ds ‘u ‘wnipidj7 ‘Q-V ‘€ ‘SBIf-3xX9 J, @ es Sssss 52 Dan L. DANIELPOL Text-fig. 4. Coquilles d’Elpidium en vue dorsale. A-C, E. n. sp. A (exemplaires de Grant Piedra). A, femelle sans oeufs. C, femelle ovigére. B, male. D, E. bromeliarum F. Miill., femelle (d’aprés Pinto et Purper, 1970). (Dimensions in text.) SYSTEMATIQUE Elpidium, n. sp. A Text-figs. 2, 3 A-D, 4 A-C, 5 G, H, 7A, B La femelle posséde une coquille qui, en vue dorsale (Text-figs. 4, A, C et 5, G), est ovoide allongée. Elle a la largeur maximale, un peu en arriére de la moitié de la longueur et représente 0.80 de la longueur de la valve gauche. 53 DIVERSIFICATION MORPHOLOGIQUE ELPIDIUM CuBA ies SR SS Si ete Ee a oe a Fae ae SRE ee 6 eee wee AS (‘3x9} UI suoIsuamiq) ‘ayeur ‘Fy ‘ayjauay ‘S *(Orpuy Ory ap saite;duiaxa) V ‘ds cu “7 ‘H ‘OD ‘ayer ‘q ‘opjamesy “qq ‘ds cu “q-y “A ‘ayyu ‘q ‘apjawas aOIp IA[VA B] AP alguIBYD Bl ap aanat1ajsod Ja AInatIgj3ue sazjassoy ‘OQ ‘g ‘ayjameas ‘y "OD ‘ds ‘u “WZ ‘q-y ‘ajesiop ana ua wnipid)q,p satjinboD *¢ “dIf-3x9 TL, 54 Dan L. DANIELPOL Text-fig. 6. Elpidium, n. sp. B, male. L’organe copulateur droit en position norm- ale sur la partie postero-ventrale du corps (P1 — P3 — thoracopodes. LAT — cdté latéral. MED — coté médial; ANT — antérieur). DIVERSIFICATION MORPHOLOGIQUE ELPIDIUM CUBA 55 L’extrémité antérieure de la coquille, pointue, tandis que celle postérieure est légérement rétrécie. L’espace de la coquille utilisé comme cavité incubatrice est réduit. Par sa forme générale, la coquille femelle ressemble plutot 4 un juvénile d’Elpidium. Seule la présence des oeufs dans le tiers postérieur de la coquille m’a donné la certitude qu’il s’agissait d’une femelle adulte. Les valves assy- métriques; la valve gauche (Text-fig. 2) ayant ume expansion postérieure qui n’existe pas chez la valve droite. Le repli de la valve gauche placé dans la région postéro-ventrale plus a l’intérieur. La valve droite recouverte par la valve gauche. La charniére posséde des fossettes cardinales sur la valve gauche. Longueur valve gauche: 0.72 mm; valve droit: 0.69 mm; largeur de la coquille: 0.59 mm. La coquille du male (Text-fig. 4, B et 5, H), plus petite que celle de la femelle, posséde aussi des valves assymétriques. La valve gauche pourvue de l’expansion postérieure; elle est un peu moins évidente que celle de la femelle. Le tiers postérieur de la coquille en vue dorsale, aigu, ressemblant a celui antérieur. La largeur maximale placée un peu en arriére de la moitié de la longueur; elle représente 0.73 de la longueur de la valve gauche. La charniére ayant des fossettes cardinales sur la valve gauche. Longueur: valve gauche: 0.66 mm; valve droite: 0.64 mm; largeur de la coquille: 0.49 mm (1). L’organe copulateur male (Text-fig. 7, A, B), massif, posséde un lobe A lamellaire pointu; le bord latéral du lobe A presque droit, le bord médial oblique par rapport au bord latéral. Le bord médial forme une excroissance digitiforme un peu en arriére de la moitié de la longueur du lobe; la moitié proximale de ce bord est sclérifiée. La position du lobe A est modifiée par le muscle M3. Dans la position normale, en repos, le lobe A forme un angle avec le corps pénien, du cété de la face dorsale. Le flagelle, inséré dans |’angle médial formé par le corps pénien et le lobe A, siége normalement sur la face externe de ce dernier. Le fiagelle est un poil glabre qui atteint la moitié de la longueur du lobe A. Le crochet accessoire, court, est massif et trés coudé. La portion proximale en forme de plaque sclérifiée est englobée dans le corps pénien s’articulant a des rainures sclérifiées rl, r2. La portion distale du crochet, légerement creuse sur la face interne, posséde une protub¢rence saillante du cdété central. Le bord distal du crochet largement arrondi. Le crochet accessoire est déplacé grace a l’action du muscle M2. Le tube éjaculateur entre dans le corps pénien par un orifice O placé prés de la base de la rainure rl. La premiere portion membraneuse est a peine visible; aprés avoir fait un coude, il entre dans le manchon étant colé a la parois interne du coté distal. Le manchon est externe et mobile par rapport au corps pénien, étant déplacé par le muscle Ml. Le manchon sclérifié est en forme d’entonnoir sygmoide. L’orifice du manchon fortement oblique (voir la Text-figure 7 B). Elpidium, n. sp. B Text-figs. 3 E, F, 5 E, F, 6, 8 A-C La femelle posséde une coquille qui en vue dorsale (Text-fig. 5, E) est ovolde. La largeur maximale, placée a la moitié de la longueur, représente environ 0.87 de la longueur de la valve gauche. L’extrémité antérieure de la coquille pointue, tandis que celle postérieure est largement arrondie. Les valves presque symétriques: celle gauche recouvre la droite. Les fossettes de la charniére placée sur la valve gauche. Longueur valve gauche: 0.75 mm, valve droite: 0.74 mm; largeur de la coquille: 0.65 mm. (1) Tenant compte de la figure de Tressler (1956), Metacypris bromeliarum citée 4 la Jamalque pourrait étre Elpidium, n. sp. A. La coquille femelle de la forme jamaiquaine en vue dorsale ressemble beaucoup 4a celle décrite ci-dessus. Dan L. DANIELPOL 56 *((yeomnz aqoy — ng ‘stdo1y — 01} !xuArajs — Js $wun3hz — AZ SumsAzi193u1 — Az faouesieqnjoid — 1g ‘ajaBeyy — [aq ‘apeasip words ‘inayepnoel> aqny — pa? fajeumxord uorder ‘inajepnoefy aqny — day finajepnoefa aqny np jewrxoid ao1fjlI0 — QO ‘uoyoUeW — BUT saire[NosnwW suor}IasUl So] quejyioddns saatztrg[os sainureI— Zi ‘I farossaooe yayoors ‘WO ‘suatugdesjUT Sinajoa1? safosnul — FIN — IW SV 24 9] — VI) 0641 ‘sading 39 OUI satde.p ‘q “T88T “TIMI “A saide.p ‘D "Y 2q0] A [IRIN “A Mnavijauosg “7 ‘d-— *(ausa}xa NO) a[BiqUaA ade RB] ap ‘[rewp ‘q ‘(ausrajur no) a[esiop aoeF ‘auoip anied e] ap ajei9uad ana ‘y ‘(eipaigd UBIDn) y ‘ds ‘u “gq ‘g ‘V ‘a[eu ‘rnaj}e[ndood auesig *L ‘BIf-3x9 JT, DIVERSIFICATION MORPHOLOGIQUE ELPIDIUM CUBA by, La coquille du male (Text-fig. 5, 6), plus petite que celle de la femelle, posséde aussi des valves presque symétriques. Le tiers postérieur de la coquille, en vue dorsale, pointu. La largeur maximale placée vers la moitié de la longueur; elle représente 0.83 de la valve gauche. Longueur valve gauche: 0.67 mm, valve droite: 0.66 mm, largeur de la coquille: 0.56 mm. L’organe copulateur male (Text-fig. 8, A, B, C) posséde un lobe A lamellaire pointu distalement. Le bord latéral de ce lobe est légérement courbé tandis que le bord médial est presque droit. Le flagelle ressemble 4 celui des espéces d’Elpidium déja décrites. Le crochet accessoire posséde une portion proximale sclérifée moins large que celle de E., n. sp. A. La partie distale du crochet accessoire est creuse, dépourvue de protubérance centrale. La parois de la cavité de ce crochet du coté distal posséde quelques striations. Quatre points (des faibles protubérances ?) sont visibles prés du bord de cette cavité. Le manchon, mobile, coudé, a l’orifice distal presque circulaire. Elpidium, n. sp. C Text-figs. 5 A-D, 8 D La femelle posséde une coquille qui en vue dorsale (Text-fig. 5, A) est ovolde. La largeur maximale 4a l’arriére de la moitié de la longueur représente environ 0.75 de la longueur. L’extrémité antérieure de la coquille pointue, tandis que celle postérieure est arrondie (elle est moins large que celle de E., n. sp. B). Les valves presque symétriques: la valve droite recourvre la valve gauche. Les fossettes de la charniére sont placées sur la valve droite. (Text-fig. 5, B, C). Longueur valve gauche: 0.80 mm, valve droit: 0.81 mm; largeur de la coquille: 0.68 mm. La coquille du male (Text-fig. 5, D) bien plus petite que celle de la femelle. Le dimorphisme de la taille trés marqué par rapport a celui des deux autres espéces déja décrites ci-dessus. Les valves sont presque symétriques. Le tiers postérieur pointu. La largeur maximale placée vers la moitié de la longueur représerte 0.8 de la longueur. Les fossettes cardinales placées sur la valve droite. Cette derniére recouvre la valve gauche. Longueur valve droite: 0.68 mm, valve gauche: 0.67 mm; largeur de la coquille: 0.54 mm. L’organe copulateur (Text-fig. 8, D) posséde un lobe A long élancé, fortement angulaire. Le bord latéral de ce lobe droit; le bord médial, légére- ment oblique, plus sclérifié que le bord opposé, a une dépression du coté distal. Le flagelle tout 4 fait semblable 4 ceux déja décrits. Le crochet accessoire du cété distal ayant une dépression sur la face interne, l’extrémité distale du crochet aigue. Le manchon ayant un orifice presque circulaire. SUR LES STRUCTURES MORPHOLOGIQUES QUI POURRAIENT ASSURER UN ISOLEMENT SEXUEL CHEZ ELPIDIUM Les trois nouvelles espéces d’Elpidium de Cuba ainsi que E. bromeliarum F. Miller (2) différent essentiellement par les détails de l’organe copulateur male et en moindre mesure par les détails des valves. (2) Je rappellerai que Elpidium bromeliarum redécrit récemment par Pinto et Purper (1970) d’aprés des exemplaires de Itajai (Brésil) posséde les Caractéristiques suivantes: coquille forte taille; 0.96 mm, longueur de la femelle et 0.84 mm le male. Le tiers postérieur de la coquille (Text-fig. 4, D) largement arrondi. Les fossettes cardinales placées sur la valve gauche. Le lobe A (Text-fig. 7, D) d’aprés Pinto et Purper (1970) est largement arrondi et présente du coté médial, prés de |’extrémité distale, une expansion conique descendante. D’aprés F. Miiller (1881), le lobe A (Text-fig. 7, C) est plus pointu et l’expansion conique est placée plus haut sur le bord médial. ‘a}I01p ajied ve] 9p ayeiguad ana ‘9 ‘ds ‘u “g ‘q ‘[!839p arrossas0e Jayoo19 — YO ‘[lel9p ‘uoyoueU ‘g “jIoIp anded Bl ap ajergued ona ‘y ig ‘ds ‘u “J ‘O-y ‘eeu inajejndod auesiQg *g “BIf-1x2 J, Dan L. DANIELPOL 58 DIVERSIFICATION MORPHOLOGIQUE ELPIDIUM CUBA 59 En revenant a l’organe copulateur male, on remarquera que les pieces qui revétent les formes les plus diverses sont le lobe A et le crochet accessoire. Par contre, le flagelle est semblable chez toutes les quatres espéces d’Elpidium., En regardant l’organe copulateur en position de repos (Text-fig. 6), sur l’animal, on apercoit qu'il est placé d’une maniére postero-ventrale et un peu latérale par rapport a l’axe longitudinal du corps, avec le lobe A orienté vers l’avant, ce qui fait que durant l’érection, il n’a pas besoin de faire une rotation de 180° comme cela se produit pour les Entocytheridae (Hart et Hart, 1969). Pendant l’accouplement, le manchon se fixe probablement dans la capsule génitale femelle. La forme du manchon est semblable chez E. bro- meliarum, E., n. sp. B et E., n. sp. C. Elle différe considérablement chez E., n. sp. A. Le crochet accessoire placé dans le voisinage du manchon pourrait avoir, non seulement un réle fixateur, mais aussi un role sensoriel comme chez les Entocytheridae. Cela expliquerait les formes diverses de l’extrémité distale sur la face interne de cette piece. Le lobe A, lamellaire, a une position trés avancée par rapport au manchon; il doit venir en contact avec la face médiale de la carapace de la femelle, jouant ainsi un role tactile. I] pourrait assurer l’isolement sexuel interspécifique. Le flagelle qui est placé sur la face ventrale (ou face externe) de lorgane copulateur ne peut pas venir en contact direct avec le corps de la femelle. Or, fait intéressant, cette piéce est semblable chez tout les Elpidium connus. Par contre, chez les Entocytheridae (voir, par exemple, les Sphaeromicolini), le flagelle qui vient souvent en contact avec le femelle revét des formes variées. La diversification des valves des trois nouvelles espéces décrites ici est bien plus discréte que celle de l’organe copulateur. Par rapport aux caractéres morphologiques différentiels des appendices qui se retrouvent seulement chez le male, les caractéres différentiels propres a la carapace sont présents chez les deux sexes. Les tailles différentes des carapaces des trois espéces d’Elpidium de Cuba pourraient jouer un role dans l’isolement sexuel. Il est 4 remarquer que la région distale antennaire du male, présentant un fort dimorphisme de la griffe Gl (voir Text-fig. 3) et jouant trés probable- ment un role important dans l’accouplement est semblable chez les trois nou- velles espéces. Le principe de la diversification des Elpidium de Cuba se retrouve aussi dans le cas des Candona du groupe neglectoida. J’ai souvent trouvé en Rou- manie, dans les sources limnocrénes, des couples d’espéces de Candona appar- tenant a la lignée neglectoida vivant parfaitement isolées du point de vue sexuel. Elles sont toujours reconnaissables d’aprés des détails de l’organe copulateur et d’aprés les particularités des valves (surtout des tailles différ- entes). En étudiant Candona aff. neglecta Sars et Candona fasciolata Petk., j’ai remarqué (Danielopol, 1969) que ce sont les piéces de l’organe copulateur male qui différent le plus chez ces deux espéces, c’est-a-dire la piece M et le crochet de la bourse copulatrice. Les valves males et femelles différent surtout par la taille; elles sont beaucoup plus grandes chez C. fasciolata que chez C. aff. neglecta. J’ai observé que la piéce M, par sa forme et par sa position, joue un role sensoriel important. Or, c’est justement cette piece qui revét les formes les plus diverses parmi les Candoninae. Par contre, les caractéres sexuels secondaires males, de méme que les poils antennaires et les palpes prehensiles du Pl sont semblables. CONCLUSIONS Dans le cas des Elpidium de Cuba, comme dans le cas des Candona du groupe neglectoida, parmi tout les caractéres, morphologiques, les piéces de lorgane copulateur male ayant un role sensoriel se diversifient le plus; elles pourraient assurer |’isolement sexuel interspécifique. 60 Dan L. DANIELPOL Les Elpfidium examinés possédent des caractéres différentiels interspéci- fiques de la carapace qui sont présents tout aussi bien chez les males que chez les femelles. Les tailles différentes des carapaces pourraient influencer l’isolement sexuel interspécifique. On doit souligner, pour finir, que la diversification de l’organe copulateur male va de paire avec la diversification de la carapace chez les Elpidium présentés ci-dessus. BIBLIOGRAPHIE Danielopol, D. L. 1969. Recherches sur la morphologie de l’organe copulateur male chez quelques ostracodes du genre Candona Baird (Fam. Cyprididae Baird). In J. W. Neale ed.: The Taxonomy, Morphology and Ecology of Recent Ostracoda, pp. 138-153, Oliver & Boyd, Edin- burgh. Hart, C. V., and Hart, D. 1969. The functional morphology of entocytherid copulatory appendages with a discussion of possible homologues in other ostracods. In J. W. Neale ed.: The Taxonomy, Morphology and Ecology of Re- cent Ostracoda, pp. 154-167. Miller, F. 1880. Wasserthiere in Baumwipfeln Elpidium bromelarium. Kosmos, 6, pp. 386-388. 1881. Descripcao do Elpidium bromelarium crustaceo da familia dos Cytherideos. Archivos do Museo Nacional, Rio de Janeiro, 4, pp. 27-34 (Apud. Pinto et Purper, 1970). Pinto, I. D., and Purper, I. 1970. A neotype for Elpidium bromelarium Miiller, 1880, (type species for the genus) and a revision of the genus Elpidium (Ostracoda). Esc. Geol. P. Alegre, Publ. Esp., 19, pp. 1-25. Tressler, W. 1956. Ostracoda from bromeliads in Jamaica and Florida. Jour. Wash- ington Acad. Sc., 46, 10, pp. 333-336. Dan L. Danielopol Limnologisches Institut Berggasse 18 1090 Wien Austria SPECIES DETERMINATION OF MOLTS FROM THE SHUBUTA CLAY OF MISSISSIPPI Rosert C. Howe anv Hersert J. Howe Indiana State University; Purdue University ABSTRACT The Shubuta Clay (upper Eocene or lower Oligocene) of southeastern Mississippi yields a diverse and exceptionally well-preserved fauna of ostra- codes and nannofossils. Recovery of more than 14,000 ostracodes provided abundant material for study of juveniles as well as adults. Of the 39 taxa recognized, seven yielded no immature specimens. Recognition of juveniles was accomplished in several ways, namely: 1) by morphologic comparisons (for example, surface ornamentation, valve outlines, and marginal denticula- tions); 2) by correlating occurrences and abundances of juveniles with the occurrences and abundances of adults; and 3) by statistical analysis of growth series using the parameters of length and height. The juveniles of Acanthocythereis howei Huff, 1970 differ markedly from the adult form, but correlation is suggested by their similar occurrences and abundances. Statistical analyses of allometric growth series and studies of occurrence and abundance indicate that “Archicythereis” yazooensis Howe, 1936 is the juvenile of Trachyleberis? montgomeryensis (Howe and Chambers, 1935). Six juvenile forms can be assigned generically but not specifically. These include members belonging to the genera Buntonia, Haplocytheridea, and two species of the genus Cytherella. Bartlett's (1949) best fit method is well suited for bivariate analysis of A-1, A-2, and A-3 growth stages. ZUSAMMENFASSUNG Der Shubuta Lehm (oberes Eozan oder unteres Oligozan) des siiddstlichen Mississippi ergibt eine mannigfaltige und aussergewohnlich gut erhaltene Fauna von Muschelkrebsen (Ordnung Ostracoda) und zwergartigen Fossilien. Die Auffindung von mehr als 14,000 Muschelkrebsen liefert eine Fille von Material, das fiir das Studium von Jungtieren sowohl als auch erwachsenen Tieren geeignet ist. Bei sieben von den 39 taxonomischen Gruppen, die erkannt wurden, fehlte die Abstreifungserscheinung. Die Erkennung von Jung- tieren wurde auf verschiedene Weisen durchgefiihrt, namlich: 1) durch morphologische Vergleiche (zum Beispiel Oberflachenverzierung, Klappenum- risse und Zahnelung des Randes); 2) durch die Aufeinanderbeziehung des Vorkommens und der Fille von Jungtieren einerseits mit dem Vorkommen und der Fille von erwachsenen andererseits; und 3) durch statistische Analyse der Wachstumsreihenfolge, bei der die Parameter von Lange und Hohe benutzt wurden. Die Jungtiere von Acanthocythereis howei Huff, 1970 unterscheiden sich ausgesprochen von der erwachsenen Form, aber eine Aufeinanderbeziehung wird nahegelegt durch Vorkommen und Fille. Das statistische Studium von allometrischen Wachstumsreihenfolgen und Studien von Vorkommen und Fille lassen darauf schliessen, dass “Archicythereis” yazooensis das Jungtier von Trachyleberis ? montgomeryensis (Howe und Chambers) ist. Sechs Jung- tierformen kénnen generisch aber nicht spezifisch bestimmt werden. Diese Formen schliessen Zugehorige zu den Gattungen Buntonia, Haplocytheridea und zwei Arten der Gattung Cytherella ein. Die am besten passende Methode von Bartlett (1949) eignet sich gut fiir die bivariate Analyse von A-1, A-2 und A-3 Wachstumsstadien. INTRODUCTION More than 14,000 ostracodes were recovered from samples of the Shubuta Clay taken at and near the type locality along the west half of the boundary between sections 3 and 10, T. 10 N., R. 7 W., across the Chickasawhay River 62 R. C. Howe ann H. J. Howe from the town of Shubuta in southeastern Mississippi (Text-figure 1). The samples were collected at approximately five foot intervals and labelled with their equivalent elevation at the type locality (Text-figure 2). Samples 175, 180, 186, 192, 200, 205, 210, 215, 220, and 230 were collected from Locality 1 whereas samples 237, 240, 250, 255, and 260 were taken at Locality 2. Sample analyses included species identification (both adult and juvenile), tabulation of occurrence-abundance data, and biometrical studies. Al] illustrated specimens are deposited in the Henry V. Howe collection (HVH) at Louisiana State University. Thirty-nine species were recognized in this exceptionally well-preserved fauna of ostracodes (Howe and Howe, 1973). During this taxonomic study we encountered varying degrees of difficulty in assigning juvenile forms to their adult counterparts. Seven species lacked juvenile representation. Of the 32 juvenile forms recognized, 21 were relatively easy to assign specifically. The purpose of this paper is to present ways in which the remaining 11 species were identified. Text-figure 1. Map showing locations of sections of the Shubuta Clay col- lected for this paper. Locality 1 is the type locality of the Shubuta Clay. Mo ts FROM SHUBUTA CLay, MISSISSIPPI 63 PREVIOUS WORK Kesling (1951, 1952, 1953) presented many of the problems associated with species recognition of instars. Several ontogenetic studies have been made (for example, Spjeldnaes, 1951; Martinsson, 1957, 1962; Hartmann, 1961; Sandberg, 1964; Sohn and Anderson, 1964). These and other papers have discussed the ontogeny of valve outline, surface ornamentation, hingement, muscle scars, marginal features, and normal pore canals; however, most papers utilizing data on immature instars have been biometrical in nature. Fowler (1909) used the work of Brooks (1886) in determining growth factors for living ostracodes and stated that each stage increased by a fixed percentage of its length approximately constant for its species and sex. This statement he named “Brook’s Law.” In spite of Fowler’s growth factors ranging from 1.26 to 1.78, Przibram (1931) used a growth factor of 1.26 for all arthro- pods assuming that mass is doubled at each molt, 1.26 being the cube root of COMPOSITE STRATIGRAPHIC COLUMN EASTERN MISSISSIPPI 5" CLAYSTONE LEDGE; FERRUGINOUS 3" CLAY;MOSTLY CALCAREOUS; QUARTZ SILTY; FERRUGINOUS; GYPSIFEROUS 9' CLAY;MOSTLY CALCAREOUS; GYPSIFEROUS re) ine) - CLAY; MOSTLY CALCAREOUS 18" CLAY; MOSTLY CALCAREOUS; QUARTZ SILTY; SLIGHTLY FERRUGINOUS; CORALS 10' CLAY; MOSTLY CALCAREOUS 12* CLAY; MOSTLY CALCAREOUS; GLAUCONITIC 5' MOSTLY COVERED PACHUTA (mret‘rr] 6° MARLY LEDGE; QUARTZ SANDY TO SILTY; GLAUCONITIC; MACROFOSSILIFEROUS Text-figure 2. Composite measured section of the Shubuta Clay deter- mined from localities near Shubuta, Mississippi. Arrows point to sampled horizons, the lowermost arrow corresponding to an elevation of 175 feet. 64 R. C. Howe ann H. J. Howe 2.0. Kesling (1953) devised a circular slide rule based on the assumed 1.26 growth factor. Later work showed that the growth factor of a particular species is not necessarily constant and that ostracodes have a wide range of growth rates (Anderson, 1964; Sohn and Anderson, 1964). Anderson formu- lated a growth law which assumed that the length-height ratio could be altered by a constant value operating uniformly with each stage of molting. This was not indicated by data from Sandberg (1964) which supported the suggestion by Reyment (1960) that the growth relationship between length and height in ostracodes is allometric during the early instars but may tend toward isometry in later ones. This is further complicated by the fact that in the final two growth stages, allometric growth may again ensue during the at- tainment of greater length by male ostracodes (Reyment, 1960). Several multi- variate analyses of ostracode data have also been presented including those of Reyment (1963, 1969). EASE OF RECOGNITION Twenty-one of the 32 types of immature forms found in the Shubuta Clay samples are easy to match with their adult counterparts. Digmocythere russelli (Howe and Lea, 1936) exemplifies this group (PI. 1, figs. 1, 2). Many of these forms have easily distinguished morphological features, such as well-developed alae, that are present in the juveniles as well as the mature forms. Most are easy to sort on the basis of the valve outline alone. Due to morphological similarity within three sets of molts, seven kinds of juveniles in the Shubuta Clay are more difficult to assign specifically. This category of recognition is illustrated by the similarity among the immature forms of Acanthocythereis multispicata Howe and Howe, 1973, Acanthocythereis spinomuralis Howe and Howe, 1973, and Henryhowella florienensis (Howe and Chambers, 1935) (PI. 1, figs. 3-8). Without the aid of a scanning electron microscope, these juveniles are almost indistinguishable. Immature forms of Haplocytheridea ehlersi (Howe and Stephenson, 1935) and Haplocytheridea montgomeryensis (Howe and Chambers, 1935) are also very much alike. Juveniles belonging to two species of the genus Cytherella are difficult to match with the mature forms due to the lack of morphological distinctness among them. Even more difficulty is encountered when trying to separate the juveniles belonging to the genus Buntonia. Juveniles of Buntonia levinsoni Huff, 1970, and Buntonia shubutaensis Howe, 1935, lack the markedly different ornamentation characteristic of the adult forms (PI. 1, figs. 11-13). Size differences do not appear to be detectable even though B. Jevinsoni is slightly more elongate as an adult; consequently, juveniles of these species remain grouped on our slides. The remaining two juvenile forms (PI. 1, figs. 10, 14) are very difficult to assign specifically because they differ morphologically from the remaining nine adult forms. They are placed in Trachyleberis? montgomeryensis (Howe and Chambers, 1935) (Pl. 1, fig. 9) and Acanthocythereis howci Huff, 1970 (Pl. 1, fig. 15), respectively, on the basis of observations and results of tech- niques discussed in the following section. Mo ts FROM SHuUBUTA CLAy, MIssIssIPPI 65 SPECIES DETERMINATION TECHNIQUES A number of morphological features permit identification of 21 juvenile representatives in the Shubuta Clay. Foremost of these is the valve outline. Obvious examples are Digmocythere russelli (Howe and Lea, 1936), Paracypris media Howe and Howe, 1973, and Bythocypris? gibsonensis Howe and Cham- bers, 1935. In contrast, species belonging to the Trachyleberidinae do not have diagnostic valve outlines. For example, all species belonging to the genera Acanthocythereis, Actinocythereis, Trachyleberis?, and Henryhowella have the same general outline (PI. 1, figs. 3-10, 14-16). Surface ornamentation is another discriminatory feature. Digmocythere russelli has a distinctive valve outline; however, a strong ventral ala is its most diagnostic feature (PI. 1, figs. 1, 2). Alatacythere ivani Howe, 1951, and Pterygocythere murrayi Hill, 1954, have similar surface features that are present in the immature forms. There are molts that have a similar surface ornamenta- tion to those of the adult forms, for example, Ouachttaia caldwellensis (Howe and Chambers, 1935) and Echinocythercis jacksonensis (Howe and Pyeatt, 1935). Other morphological features are less easy to use. Muscle scar patterns tend to be consistent from early larval stages through the adult; however, the patterns within the Trachyleberidinae are so similar from species to species that this is a difficult criterion to use. Moreover, muscle scar patterns are com- monly more difficult to observe than the features mentioned above. Study of pore canals requires high magnification and the number of normal and radial pore canals tends to increase throughout ontogeny. A distinctive hinge struc- ture sometimes occurs in early stages but hinge elements may be virtually identical in several kinds of immature forms such as in juveniles belonging to the Trachyleberideinae. Marginal denticulation is a fairly constant character in juveniles whose adult forms have this feature; too often, however, com- paction has destroyed these distinguishing features. Eleven juvenile forms in the Shubuta Clay lack obvious discriminatory features. Two species of the genus Acanthocythereis and one species of Henry- howella have juveniles which are nearly identical. Immature specimens of Acanthocythereis spinomuralis can be recognised under high power because they have characteristic subcircular fossae with tiny spines projecting inward from the muri. Molts of 4. multispicata and H. florienensis are separable by plotting a scattergram of length versus height (Text-fig. 3). The largest juveniles are nearly as large as H. florienensis; consequently, they must be the last immature stage of A. multispicata. Six of the remaining eight kinds of juveniles can be assigned generically but not specifically. These include forms which belong to the genera Buntonia and Haplocytheridea and two species of the genus Cytherella. They have valve outlines characteristic of their genus, but lack specific characters. The last two juvenile types appear to match with Acanthocythercis howei and Trachyleberis? montgomeryensis, respectively, on the basis of occurrence and abundance data (Text-fig. 4). In particular, immature forms assigned to 66 R. C. Howe anp H. J. Hower A. howei and the adults show an occurrence and abundance pattern that is unusual for species occurring in the Shubuta Clay. They are one of only two species that occur chiefly within the upper half of the type Shubuta section. For these reasons we group the two forms together in spite of their considerable morphological differences (Pl. 1, figs. 14, 15). A scattergram of length versus height further indicates that these juveniles are the precursors of the indicated adults (Text-fig. 5). Even greater morphological differences are noted between Trachyleberis? montgomeryensis and its assigned juveniles (Pl. 1, figs. 9, 10). Occurrence and abundance data for the immature individuals and adults is somewhat less conclusive than those for A. howei; consequently, the lengths and heights of these forms were measured and plotted on a scatter- gram. Due to breakage of spines, parameters were determined as shown in Text-figure 6. Because of allometric growth the measurements were loga- rithmically transformed. Designation of instars followed the system used by Christensen (1963). Henryhowella florienensis 580 Acanthocythereis multispicata © 500 2420 «340 HEIGHT IN MILLIMETERS 2260 | S ) wy e e 580 (S) \O \O e » 740 °820 ©900 ~980 LENGTH IN MILLIMETERS Text-figure 3. Scattergram for length and height of Henryhowella florien- ensis and Acanthocythereis multispicata. Adult males delineated. All speci- mens collected at elevation 205 feet. Mo tts FRoM SHuBUTA CLay, MISSISSIPPI 67 WO oo alo tO noo ~~ O'o nS COD ROOHAN NMAKHNO AAA AMUN HNN 200 100 Adults 3) = : 5 =| 200 Larvae 100 Acanthocythereis howei iN O.40:0) O71N,.0 tO. CO fC OLAS 20709 FAA AN AAA nal aia an cd ae Adults fx e E <3 200 - Larvae 100 7 a Trachyleberis? montgomeryensis Text-figure 4. Occurrence and abundance diagram for adults of A cantho- cythereis howei and Trachyleberis? montgomeryensis and the juveniles as- signed to them. 68 R. C. Howe anp H. J. Howe » 580 © 500 420 ~ 340 HEIGHT IN MILLIMETERS «260 oO oO © oO (eS) S iS) oO oO O =r NX oO oO WY WY O Is (08) ON ON es e e e e e e LENGTH IN MILLIMETERS Text-figure 5. Scattergram for length and height of Acanthocythereis howei and the juveniles grouped with them. Adult males delineated. All specimens collected from elevations 200 to 205 feet. 1.060 BELG Text-figure 6. Diagram to illustrate how parameters of length and height were determined for statistical analysis. Mo_tTs FROM SHuBuTA Cray, MIssIssIPPi 69 In order to attempt to match the juveniles in question with the adults of T ? montgomeryensis, Bartlett's (1949) “best fit” line was found using data for the A-1, A-2, and A-3 growth stages. A-4 molts were also present in the samples but their extremely fragile nature negated their use; besides, Bartlett’s method required grouping data into three sets preferably of equal numbers of observations in ascending order of magnitude. At first, thirty specimens each of the A-1, A-2, and A-3 stages were randomly selected for statistical treat- ment; however, it soon became apparent that males could be distinguished within the A-1 population. The males are considerably more elongate than the females at this stage; therefore, for the A-1 data, presumed males were arbitrarily excluded. If two log-transformed variables are related by a linear function, then the relationship between them may be expressed by a “best fit” line with the formula YS oe Px where a is the Y-intercept estimated by the expression A= — 2X: and f is the slope cf the line estimated by B = Ys — Yi (X, Y equal means of the whole sample population; = = Xs, Ys equal means of the A-1 population; X,, Yi X: — Xi — equal means of the A-3 population.) Statistical results are listed in Table 1. Text-figure 7 illustrates that the mean adult female of T? montgomeryensis clearly fits the prediction made possible by the ‘‘best fit” line whereas the mean adult female of Actinocythereis purii (Pl. 1, fig. 16), also considered to be possibly the adult form for this set of juveniles, is well off the line. As expected, the adult males of T? mont- gomeryensis plot well off the line. In conclusion, due to the availability of the A-1, A-2, and A-3 molt stages and due to the results of the ‘best fit” line method, we believe that the forms called “Archicythereis” yazooensis in the literature are in reality the immature representatives of T? montgomeryensis. DIFFICULTIES ENCOUNTERED Although the Shubuta Clay yielded a remarkable ostracode fauna in which most species displayed at least five growth stages, it does not seem possible to solve all the problems which arose in regard to identification of juveniles. A significant problem is to explain why seven species apparently show no immature forms. Reyment (1960, pp. 14-17) suggested that where a sediment contains only adults, perhaps they lived a different mode of life than the larvae. He further has stated that the adults may have been selectively transported; however, it seems unlikely that there was much transport prior to deposition in the case of the very fine-grained Shubuta Clay because more than 99 percent of the material is finer than one-sixteenth of a millimeter. Another problem which causes concern is how to accurately measure the smallest larval stages. The adults, the A-1, the A-2, and usually the A-3 stages can be measured easily but the A-4 individuals are so small that accuracy of measurement is impaired. At higher magnification, errors are magnified. 70 R. C. Howe anp H. J. Howe Table 1. Statistical results for Trachyleberis? montgomeryensis, molts assigned to that species, and Actinocytherets purit. All specimens collected at elevation 192 feet. Symbols follow those of Simpson, Roe, and Lewontin, 1960. xX S OR. MALES (N=22) Log Length 0.9822 0.0151 0.9474-1.0067 Log Height 0.6697 0.0158 0.6277-0.6962 FEMALES (N=22) Log Length 0.9543 0.0132 0.9138-0.9705 Log Height 0.6872 0.0172 0.6539-0.7187 A-1 (N=30) Log Length 0.8437 0.0115 0.8119-0.8606 Log Height 0.5850 0.0140 0.5543-0.6093 A-2 (N=30) Log Length 0.7357 0.0128 0.7038-0.7621 Log Height 0.4938 0.0098 0.4851-0.5182 A-3 (N=30) Log Length 0.6315 0.0147 0.6022-0.6539 Log Height 0.4018 0.0167 0.3795-0.4213 Actinocythereis purli-FEMALES (N=16) Log Length 0.9185 0.0082 0.9079-0.9320 Log Height 0.6642 0.0188 0.6321-0.6865 Data for Grouped A-1, A-2, and A-3 specimens N=90 Sx2=17089 K=30 Sxy= 12869 B=0.863 S,7= 19144 A=-0.1425 95% cl for=0.8630.022 Mo Ts FROM SHuBUTA Cray, MIssIssIPPi 71 The most difficult problem is how to separate juveniles which appear to be morphologically identical when there are obviously two species of adults present in the sample. Size analysis and higher magnification are possible solu- tions; otherwise, we are left with an unsolved problem as in the case of the juveniles of the genus Buntonia, 0.70 0.65 0.60 0.55 0.50 LOG HEIGHT O45 040 Ve 055 12) Ne) uy oO uN oO uN oO uN oO uN \o éY ft ie @) cO On oO Oo e) e e e ° © 8 6 e ° e i.e) o oO oO oO oO oS ‘S) qo cd LOG LENGTH Text-figure 7. Plot of the means listed in Table 1 and the position of the mean of the final growth stage predicted by the “Best Fit” line — dashed. (@ = means of molts assigned to Trachyleberis? montgomeryensis and mean predicted by statistical] analysis; X = means of adult males and females of T? montgomeryensis; and, 0 = mean for females of Actinocythereis purii) Measurements are in mm. REFERENCES Anderson, F. W. 1964. The law of ostracod growth, Paleontology, vol. 7, pp. 85-104. Bartlett, M. S. 1949. Fitting a straight line when both variables are subject to error. Biometrics, vol. 5, pp. 207-212. Brooks, W. K. 1886. Report on the Stomatopoda collected by H. M. 8. Challenger during the years 1873-6. Challenger Report, Zoology, vol. 16, pl. 2. Christensen, O. B. 1963. Ostracods from the Purbeck-Wealden beds in Bornholm. Dan- marks Geologiske Undersgelse, ser. 2, pp. 1-58. 72 R. C. Howe ann H. J. Howe Fowler, G. H. 1909. The Ostracoda. Biscayan Plankton, Pt. 12. Trans. Linn. Soc. Lond. (Zool.), vol. 10, pp. 219-336. Hartmann, G. 1961. Beitrag zur ontogenie des ostracoden-schlosses (mit beschreibung von 2 neuen arten). Zeitschrift fur wissenschaftliche Zoologie, vol. 65, pp. 428-452. Howe, R. C., and Howe, H. J. 1973. Ostracodes from the Shubuta Clay (Tertiary) of Mississippi. Jour. Paleont. vol. 47, No. 4, pp. 629-656, pls. 1-5. Kesling R. V. 1951. The morphology of ostracode molt stages. I\linois Biol. Monograph, vol. 21, pp. 1-126. 1952. Doubling in size of ostracode carapaccs in each molt stage. Jour. Paleont., vol. 26, pp. 772-780. 1953. A slide rule for the determination of instars in ostracode specics. Contr. Mus. Geol. Univ. Mich., vol. 11, pp. 97-109. Martinsson, A. 1957. Ontogeny and development of dimorphism in some Silurian ostra- codes: a study on the Mulde marl fauna of Gotland. Bull. Geol. Instn. Univ. Uppsala, vol. 37, pp. 1-40. 1962. Ostracodes of the family Beyrichtidae from the Silurian of Gotland. Geol. Instn. Univ. Uppsala, Bull. 41, pp. 1-369. Przibram, H. 1931. Connecting laws of animal morphology. University of London Press, 62 pp. Reymenf, R. A. 1960. Studies on Nigerian Upper Cretaceous and Lower Tertiary Ostra- coda. Part 1. Senonian and Maestrichtian Ostracoda. Stockholm Contr. Geol., vol. 7, pp. 1-238. 1963. Studies on Nigerian Upper Cretaceous and Lower Tertiary Ostra- coda. Part 2. Danian, Paleocene, and Eocene Ostracoda. Stockholm Contr. Geol., vol. 10, pp. 1-286. 1969. A multivariate paleontological growth problem. Biometrics, vol. 25, pp. 1-8. Sandberg, P. A. 1964. The ostracode genus Cyprideis in the Americas. Stockholm Contr. Geol., vol. 12, 178 pp. Simpson, G. G., Roe, A., and Lewontin, R. C. 1960. Quantitative Zoology. Harcourt, Brace, and World, Inc., New York. Sohn, I. G., and Anderson, F. W. 1964. The ontogeny of Theriosynoecum fittoni (Mantell). Palaeontology, vol. 7, pp. 72-84. Spjeldnaes, N. 1951. Ontogeny of Beyrichia jonesi Boll. Jour. Paleont., vol. 25, pp. 745- 755. Robert C. Howe Department of Geography and Herbert J. Howe, Geology Department of Geosciences Indiana State University Purdue University Terre Haute, Indiana 47809 Lafayette, Indiana 47907 U.S.A. WESEAS Mo ts FROM SHuUBUTA CLay, MIssIssIPPI 13 DISCUSSION Dr. A. Liebau: You have studied well ornamented forms. I have observed that the ornament changes in the ontogenies of such species follow certain rules. As an example, variation in the mesh configuration of instars is often followed by place constance in the reticulation of adults, while a contrary development seems to be impossible. I hope that I can touch upon these ornament relation- ships in my paper. Dr. H. Uffenorde: Did you observe any sign of bioturbation in the Shubuta Clay sequence? At least in neritic environments of low energy level, bio- turbation seems to be of some importance in destroying much of the more fragile shell material. Evidently bioturbation causes pre-diagenetic changes in faunal composition. This seems to be true also with regard to the relation between the abundance of adults and juveniles. Dr. I. G. Sohn: The first slide showed the abundance of adults and juveniles. There should be more juveniles than adults if it is an actual population sample. Dr. H. J. Howe: The discrepancy is probably due to selective preservation. The A-3, A-4, and A-5 molts in particular are very fragile and can be easily broken during clay compaction. Selective sorting may be a partial factor; how- ever the wide variations in size observed in the Shubuta specimens do not indicate that sorting removed the smaller specimens to any significant degree. In the case of Acanthocythereis howei and Trachyleberis? montgomeryensis, occurrence and abundance data and scatter diagrams of growth demonstrate the correctness of the molt assignments that we have made. Several hundred specimens, representing both species, were gleaned from the samples making them among the most abundant elements in the Shubuta Clay. Dr. J. Hazel: The species montgomeryensis is not a Trachyleberis, in my opinion. Dr. H. J. Howe: There is a question regarding the generic assignment of Trachyleberis? montgomeryensis. The evidence presented here shows that the form identified as “Archicythereis” yazooensis in the literature is actually the molt of Trachyleberis? montgomeryensis, The generic assignment of the species is provisional pending revision of the genus Trachyleberis and other trachyleberid genera. 74 Figure hy Ae 3, 4. 5, 6. 7, 8. 9, 10. 11. 12. 13. 14, 15. 16. R. C. Howe anv H. J. Howe EXPLANATION OF PLATE 1 (All illustrations approximately x50) Digmocythere russelli (Howe and Lea) 1. Right valve, HVH 9333, from elevation 180 feet. 2. Juvenile right valve, HVH 9759, from elevation 175 feet. Acanthocythereis multispicata Howe and Howe 3. Female right valve, HVH 9376, from elevation 237 feet. 4. Juvenile right valve, HVH 9379, from elevation 220 feet. Acanthocythereis spinomuralis Howe and Howe 5. Juvenile right valve, HVH 9760, from elevation 180 feet. 6. Female right valve, HVH 9380, from elevation 180 feet. Henryhowella florienensis (Howe and Chambers) 7. Female right valve, HVH 9399, from elevation 237 feet. 8. Juvenile right valve, HVH 9761, from elevation 192 feet. Trachyleberis? montgomeryensis (Howe and Chambers) 9. Female right valve, HVH 9360, from elevation 175 feet. 10. Juvenile right valve, HVH 9363, from elevation 230 feet. Buntonia levinsoni Huff Female left valve, HVH 9389, from elevation 186 feet. Buntonia sp. Juvenile left valve, HVH 9762, from elevation 192 feet. B. shubutaensis Howe Female left valve, HVH 9391, from elevation 230 feet. Acanthocythereis howei Huff 14. Juvenile right valve, HVH 9367, from elevation 220 feet. 15. Female right valve, HVH 9369, from elevation 220 feet. Actinocythereis purii Huff Female right valve, HVH 9386, from elevation 186 feet. MIssIssIPPI > ss < =| O < ry =) je} N a fe) 4 fo yn = a) o) = N THE LEFT-RIGHT VARIATION OF THE OSTRACODE ORNAMENT A. LrEBAU Geolog. Palaontolog. Inst., Tiibingen ABSTRACT In the introduction a general classification of ostracode ornaments is out- lined, together with an hypothesis on calcification contro] of smaller ornament details. In examples from the genera Loxoconcha, Aurila, Beyrichia, and Oertliella the ornament variation between left and right valve of the same carapace is studied. It seems to be a general rule that this “inter-valve variation” reflects the inter-individual one. Pits, meshes, and spines, which vary in their number from left to right side of a carapace, also vary when corresponding valves of different individuals are compared. Furthermore, intraspecific constancy of position of ornamental details is recognizable by the comparison of the two valves of a carapace. In respect to the numerical variation of sculpture details, left and right valves are like two separate “specimens” (i.e. examples for a species )and can be used for “twin researches in fossil ostracodes”’. ZUSAMMENFASSUNG In der Einleitung wird eine allgemeine Klassifizierung von Ostrakoden- Ornamenten umrissen. Angefiigt ist eine Hypothese tiber Kalzifikationsein- fliisse auf die Ausbildung kleinerer Feinskulptur-Elemente. An Beispielen aus den Gattungen Loxoconcha, Aurila, Beyrichia und Oert- tliella wird die Beziehung im Ornament zwischen linker und rechter Klappe untersucht. Anscheinend entspricht es einer allgemeingiltigen Regel, dass die Ornament-Variabilitat von Klappe zu Klappe diejenige zwischen konspezifischen Individuen widerspiegelt. Griibchen, Maschen und Stacheln, die beim Vergleich der beiden Seiten eines Gehauses numerische Unterschiede zeigen, variieren ebenfalls, wenn einander entsprechende Klappen verschiedener Individuen verglichen werden. Auch Elementkonstanz im Ornament ist auf diese Weise er- kennbar. Hinsichtlich der numerischen Variabilitat von Skulptur-Details sind linke und rechte Klappe zwei vollwertige “Exemplare” (d.h. Beispiele fiir eine Art) und kénnen quasi zu einer “Zwillingsforschung an fossilen Ostrakoden” benutzt werden. INTRODUCTION This paper is part of a more general study of ostracode ornament evolu- tion. Some fundamentals were given in Liebau (1969, 1971). Two results con- cerning this subject, which have not yet been published, are presented as pre- liminary notes in the following introduction. They illustrate the importance of ornament variation analyses. The scanning electron photographs are courtesy of the Cambridge Co., Dortmund. The presentation of this paper at the Delaware conference has been sup- ported by the Deutsche Forschungsgemeinschaft. The finer sculptural elements on ostracode valves, i.e.: pits, meshes, spines, tubercles vary in number and configuration but also may be constant. In many ostracode studies these ornamental details are treated in a very general way. But there are reasons at least for distinguishing constant elements from varying ones: 78 A. LiesBau 1) Constant spines, meshes can be used as markings with defined positions (e.g. when ontogenetical allometries are observed). 2) Constant ornament details which are individually fixed in the genetic plan (i.e. can be mutated individually), are each, actually or potentially, taxonomical features. 3) Varying meshes occurring besides constant ones seem to reflect certain calcification stages of the shell. Such observations may reveal progressive stages of carapace construction or show calcification contro] by ecological in- fluences (temperature, salinity). They help to distinguish ecologically-caused ornament changes from true phylogenetical developments. In respect to their genetic plan the following main ornament classes are distinguished: position of ornament single element individual evolution relation to class and element number _ of single element pore systems macro- constant possible usually ornament present meso- constant impossible or usually ornament not observed present proto- varying impossible usually ornament present micro- varying impossible spines: possible ornament pits: absent As mentioned before, the occurrence of numerically varying ornamental elements can often be correlated with certain calcification stages. An hypothesis on calcification-controlled ornamental changes includes fundamental obser- vations by Herrig (1965, 1966). These ornamental developments have been observed in the Trachyleberididae s./. (including Hemicytherinae), and they are also present in most, if not all, of the other Cytheracea. The calcification hypothesis needs more proof and documentation of exam- ples than is possible at this time. Nevertheless the complex of observations and interpretations is outlined here, as it helps in understanding the problems of sculpture analyses: 1) Macroreticulation (a system of meshes with constant positions) is re- placed by microreticulation (varying meshes, smaller than neighboring macro- meshes), in cases where a certain calcareous shell layer is reduced. In the final phase of this process a fine pitting or even a smooth surface is observed in place of the macroreticulation. But also in smooth specimens all genetic in- formation about the macroreticulation may still be present, although not ex- pressed in the phenotype. 2) Microconation (spinelets varying in number) does not occur together with microreticulation. It is, therefore, supposed that these two ornamental LEFT-RIGHT VARIATION IN ORNAMENT 79 components belong to opposite calcification stages of “Herrig’s shell layer”. There are likewise transitions from microconate macroreticulation to smooth surfaces. This type of smoothing down of the ornament corresponds to the interpretation of the “celation” by Sylvester-Bradley & Benson (1971). A use- ful rule is that meshes with microconate meshwalls have constant positions. 3) In the growth towards the adult stage the shell layer is gradually thick- ened. Therefore, microreticulate larvae may progress to macroreticulate adults, whereas the reverse combination has not been observed. Microconate adult orna- mentation is obviously not preceded by a microreticulate one in the last instar. In phylogenetic series ornamental changes in both directions are possible, corresponding to thickening as well as to thinning-out of that shell layer. This means that macroreticulation can be reduced and rejuvenated in a lineage with- out changes in the mesh configuration. In shorter periods similar ornamental alterations may be caused by eco- logical influences in the writer’s opinion. Decreasing temperature and salinity may induce weak calcification of the shell and in this way bring about the replacement of macro- by microreticulation. “Microreticulation’ and “macroreticulation’’ were defined in Liebau (1971). ‘“Microconation” replaces “Mikrotuberkulation” of the same publica- tion. All these terms should be regarded as provisional until a comprehensive terminological paper is published and discussed. This terminology is in prepara- tion. The data and comments presented herein show some of the problems, in the study of ostracode ornamentation. These problems must be solved, because Cytheracean ornamentation is of major importance taxonomically. An im- portant discussion of the application of homologized ornamental features is that of Benson (1972). Left-right variation studies will be, I hope, a practical tool to indicate the use of ostracode ornamentation where only a few speci- mens are available. THE LEFT-RIGHT VARIATION While studying the ornamental variation of ostracode species I have regularly observed that intraspecific variable ornamental details also show differences from the left to the right valve of the same carapace. Intraspecific element constance is also reflected by these inter-valve relations. Of course certain exceptions must be noted. On one hand the sculpture pat- terns of the two valves of an ostracode are normally symmetrical. On the other hand, in some cases conspicuous differences are observed, e.g. in con- nection with a specialized carapace construction or with the sexual dimorphism. Such examples are excluded from the following considerations. Only the ornamental fields which are represented by equivalent patterns on both sides of the carapace, are considered here. Intraspecific ornamental variations due to changing (paleo-) ecology, are not reflected in inter-valve differences (as the two valves of a carapace are from the same biotope). 80 A. LieBAu -) & b ° mn 4 fe) 02 G60 ° Oe ° 0°83 00 <9 fo} re) lant = . 299 or Oo pen S FOES 2930°° 9 o C 5 899 Ce@.0 (8,0 02 BAS U£Qe02°0 O wet ae CO Oe Gg AO 3606072 wee e° oes OS $9 990.0% 65 8 89 SL e Coce Biche Seve SI) S S ae We, 0% 0 S7 ooo © Sica?) = esses) A Seo C $4022 0 oS SSS a oJ 290 0°35 20° 252070 fakes 3°Q%0 0%, 99,0°S65 2000. “5 ra) oO S90 Cele) ne) 909 _ ® 2° 9 O59 00 “No Yeo 00959995 0009% 6 Og oF > Ne 101020 0°.604°0.6 9 ES We Ue p oes. eee OS SiG OOS ei) O93 0 5 wes 9595 Se5nOa 10 7O@ COP > Ze Ne So gO OCs ae eal 4 Ja v Yo 000.0~,, - CHa 5 [650° 6298) JeAce - ON a hal ee) Goa es Text-fig. 1. Loxoconcha sp. 1, Recent, Adriatic Sea. A and B. Left and right valve of the same carapace (left valve: drawing inverted). C. “Inter- valve” comparison of Li and R1. D. “Inter-individual” comparison of two right valves. Scale: Length of the R1 0.77 mm. Signatures: + ornament details missing in one of the compared valves vy v_ general differences in number and arrangement of ornament details (Further explanations in the text). L1 —S>S= SS sOs8 FPS55U0 8 C2 Sonn IS oO NS CS CSSI0VU OS Text-fig. 2. Loxoconcha sp. 2, Recent, Mauritius. Scale: Length of the L1 0.67 mm. LEFT-RIGHT VARIATION IN ORNAMENT 81 A few examples may illustrate the principle idea of the left-right ornament comparisons: 1) Loxoconcha sp. 1 Recent, beach sample, Adriatic Sea near Pessaro, Italy. The drawings A and B in Text-fig. 1 show the mesh patterns of left valve (L1) and right valve (R1) of the same carapace. Some sieve pores observed in scanning electron microscope photographs, were used as the basis for the drawings. In Text-fig. 1C all meshes and pores, which are common to both valves, are plotted within the outline of the right valve. Zones of varying meshes (differing from valve to valve in number and arrangement) are marked by groups of “V”. Single meshes missing in one of the patterns are noted with a cross. In the same way (in Text-fig. 1D) the right valve (R2) of a second carapace is compared with the first right valve (R1). Now the inter-valve variation (R1/L1) and the inter-individual one (R1/R2) can be compared. In both cases the result is about the same. 2) Loxoconcha sp. 2 (Loxocorniculum sensu Benson & Coleman, 1963) Recent, beach sample, Mauritius (Indian Ocean). In Text-fig. 2B the valves L1 and R1 (belonging to the same carapace) are compared as in Text-fig. 1C of the first example. Both valves have about the same mesh pattern. Then a rather differing L2, small, with thick mesh walls, has been chosen for the comparison with the L1. The results of the analyses L1/R1 compared to L1/L2 show, accordingly, that the mesh pattern is con- stant. 3) Aurila sp. 1 Recent, beach sample from the lagoon of Sao Martinho do Porto, Portuguese coast. Li compared with R1 (Text-figs. 3A, 3B, analysis: 3C) demonstrates that the pores and some of the meshes are constant, while others, especially small ele- ments within the outlines of larger ones, vary. The uppermost pit row in the L1 has no equivalent in the Rl. The comparison of the L1 with the L2 of another carapace yields about the same information on the ornamental vari- ability as before (L1/R1). Only one exception is obvious: because of the cara- pace asymmetry, which is one of the characteristics of this genus, left and right valves do not correspond in the upper peripheral pit row. This problem does not occur, when left valves (or right ones) are compared. Nevertheless, many other meshes are common both to the two valves of a carapace and to the left valves of different individuals. These meshes are assumed to be constant. 4) Aurila convexa (Baird, 1850) Recent, same sample as in 3. Li and R1 of the same carapace and Li and L2 of different carapaces are compared, all as in the example before. Text-figure 4 shows the L1 mesh pattern and the comparisons L1/R1 and L1/L2. Finally, the ornamental rela- tions between Aurila convexa (L1) and Aurila sp. 1 (L2 of the example be- fore) are demonstrated in Text-fig. 4B. The result shows a number of meshes to have supra-specific occurrence, and probably a phylogenetic relationship. 5) Beyrichia peponulifera Martinsson, 1962, Mulde marl, Mulde, Silurian of Gothland. 82 A. LieBau Text-fig. 3. durila sp. 1, Recent, Portuguese coast. — Scale: Length of the L1 0.76 mm. Text-fig. 4. Aurila convexa, Recent, Portuguese coast. Scale: Length of the L1 0.76 mm. LEFT-RIGHT VARIATION IN ORNAMENT 83 JA oy o So W/o A R1 of ee ae C ° mine oe 4 ° 2 Ms & 2 oJ ~ 4 ae Qe wy Wd ~ ON MMMM 3 \, ull Yi” a C Text-fig. 5. Beyrichia peponulifera, Silurian, Gothland. — Scale: Length of the Ri 1.55 mm. A. LieBAU Plate 1 Plate 1.— Fig. 1. Oertliella sp. 1, Eocene, southern France. Anterior portion of the right valve. Scale as in figure 2. Fig. 2. Same carapace as in figure 1, anterior portion of the left valve. Scale: Height 0.44 mm (incl. spines). LEFT-RIGHT VARIATION IN ORNAMENT 85 Only a pattern of spines and tubercles is present. Both the results of the inter-valve and the inter-individual comparisons show that certain spines of the velar row have constant positions. Additional information taken from Martinsson (1962) confirms that these spines are constant; at least some of them are also found in other species: one, named the “calcarine spine” (Mar- tinsson), has suprageneric distribution. 6) Oertliella sp. Lower Cuisian (L. Eocene), Tuilerie de Gan near Pau (southern France). The anterior part of left and right valve of the same carapace are figured on Plate 1. This very rich ornament consists of phylogenetically old, constant components, and varying younger ones. The meshes and the larger lateral spines show the same configuration on both valves and, indeed, they are constant (and of at least Lower Cretaceous age). But even in the confusing spine con- centrations at the anterior margins left and right valve correspond in nearly all details. The explanation: these spines and spinelets have genetically fixed places. Each of them has an homologous feature corresponding with Cretaceous species and genera of Cytherets s. str. Another class of spinclets surrounds the mesh openings. They vary in number; sometimes three or four of them are found on one valve, while the other valve has only two at the same place. Accordingly there is a corresponding inter-individual numerical variation. (Another conspecific specimen from the same sample is figured in Liebau, 1971, p. 57). These examples indicate that there is a relationship between inter-individual and inter-valve variation of ostracode ornament. Of course this argument is not sufficient for an exact statement, but nevertheless many other species have been studied in this way and no observation has been made to the contrary. In ostracode studies (left-right comparisons may have taxonomic interest when only a few carapaces are available. In those cases the two valves of a carapace can be used (except as noted before) in respect to the ornamental variation like two conspecific specimens. Moreover these “specimens” offer some advantages which are unusual among fossils: they are with certainity of the same stratigraphic age, of the same sex, of same ontogenetic stage, have lived in the same biotope and belong to the same population. They can be studied like twins from the same environment! REFERENCES Benson, R. H. 1972. The Bradleya problem, with descriptions of two new psychro- Spheric ostracode genera, Agrenocythere and Poseidonamicus (Ostracoda: Crustacea). Smithsonian Contrib. Paleont., 12, pp. 1- 138, 67 figs., 4 tbls., 14 pls.; Washington, D.C. Herrig, E. 1965. Cythercis reticulata varia ssp. n. cine neue Ostracoden-Unterart aus der Rtigener Schreibkreide (Unter-Maastricht). Ber. geol. Ges., DDR, 10 (4), pp. 403-419, 5 figs., pls. I-IV, Berlin. 1966. Ostracoden aus der WeiBen Schreibkreide (Unter-Maastricht) der Insel Riigen. Palaont. Abh. A, II (4), pp. 693-1024, 144 figs., pls. I-XLV, Berlin. 86 A. LieEBAU Liebau, A. 1969. Homologisierende Korrelationen von Trachyleberididen-Ornamen- ten (Ostracoda, Cytheracea). Neues Jarb. Geol. Palaont., Mh., 1969 (7), pp. 390-402, 4 figs., Stuttgart. 1971. Homologe Skulpturmuster von Trachyleberididen und verwandten Ostrakoden. Dissertation at the Technical University Berlin, pp. 1-118, 32 figs., Berlin. Sylvester-Bradley, P. C., and Benson, R. H. 1971. Terminology for surface features in ornate ostracodes. Lethaia, 4, pp. 249-286, 48 figs., Oslo. Alexander Liebau Geolog. Paladontolog. Inst. Sigwartstr. 10 D-74 Tubingen Germany DISCUSSION Dr. I. G. Sohn: You have proved that practically everything on the ostracode carapace is genetically controlled. But I wonder about those ostracodes that are not symmetrical. What happens when they have right and left valves that are distinctly different. Dr. Liebau: Of course I cannot work with carapaces which have e.g. a nodose right valve and a smooth left one. But these cases are few and easy to recognize. In many species the ornamentation at the periphery of the valves shows sig- nificant differences. The Aurila examples have been chosen in order to demon- strate this problem. THLIPSURA JONES AND HOLL: A REDESCRIPTION OF THE TYPE SPECIES Rosert F, LuUNpDIN AND LEE E. PETERSEN Arizona State University ABSTRACT The type species of Thlipsura Jones and Holl, 1869 is redescribed and reillustrated. In addition, one new species of Thlipsura from the Silurian of England is illustrated. The hinge and contact margin structures of Thlipsura are defined and illustrated. These are concluded to be critical in the definition of the genus. Comparison of T. corpulenta with numerous North American and European species now and formerly placed in TAlipsura is made, and a conse- quent revision of the species composition of the genus is presented. Thlipsura is found to be restricted to the Silurian of Europe and North America. RESUME L’espéce de type de Thlipsura, Jones et Holl, 1869 est décrit et illustré encore une fois. En plus, une des nouvelles espéces de TAlipsura du Silurian d’Angleterre est illustrée. Les structures de la charniére et du bord de contact de le Thlipsura sont definis et illustrés. Celles-ci deviennent critiques dans la definition du genre. Une comparison est faite entre le T. corpulenta avec plusieurs espéces d’Amerique du Nord et d’Europe placées auparavant et en- core maintenant dans Thlipsura et il y a une présentation d’une révision résultante de la composition due genre des espéces. On trouve que Thlipsura est limité au Silurian d’Europe et d’Amerique du Nord. INTRODUCTION The genus Thlipsura was erected by Jones and Holl in 1869 on the basis of material from the Woolhope beds (Wenlockian) of England. T. corpulenta Jones and Holl, 1869, has been generally recognized as the type species (UI- rich and Bassler, 1923; Swartz, 1932; Bassler and Kellett, 1934), as well it should be according to the International Code of Zoological Nomenclature. This species therefore took on special significance when Ulrich (1894) estab- lished the family Thlipsuridae, including in it Thlifsura, Phreatura and Octonaria. The original illustrations of T. corpulenta are remarkably accurate. Unfortunately, subsequent authors (Ulrich and Bassler, 1923; Swartz, 1932; Bassler and Kellett, 1934; Kesling, 1961; Krandijevsky, 1968) have revised or perpetuated revised versions of Jones and Holl’s (1869) drawings without adequate knowledge of the true appearance of the type specimen. This has led to a grossly misleading diagnosis of the genus (Krandijevsky, 1968) and con- fused revisions of the family Thlipsuridae (Swartz, 1932 and Krandijevsky, 1968). In view of these problems we have undertaken this study in order to: (1) redescribe and reillustrate the type species of Thlipsura. (2) establish the range of variation within T. corpulenta. (3) determine the validity of the various species and varieties of Thlipsura erected by Jones and Holl (1869) and Jones (1887). (4) establish the species composition of TAlipsura especially with respect to North American forms. These are the main objectives of this re- port. We in no way intend this to be a revision of the Thlipsuridae, a project which is in our future plans. Nevertheless, it will be necessary to comment 88 R. F. LunpIn anp LEE E, PETERSEN on and make special observations about other thlipsurid genera. These are meant to be preliminary in nature. Hopefully, this report will serve to clarify the very basis of the family Thlipsuridae and act as a starting point for a complete revision of this group. ACKNOWLEDGMENTS - We wish to express special gratitude to Professor Anders Martinsson (Up- psala University) for supplying large collections of Thlipsura and Mr. David Siveter (University of Leicester) who guided Lundin in the field where addi- tional collections were procured. Dr. R. H. Bate (British Museum of Natural History), Dr. R. H. Benson (United States National Museum of Natural History), M. J. Copetand (Geological Survey of Canada), A. L. Guber (Penn- sylvania State University), and A. F. Abushik (All-Union Scientific Research Geological Institute, Leningrad) have been most helpful in supplying type specimens which have been critical to this study. To all of these people we express our deepest appreciation. Finally special thanks are given to the University Grants Committee of Arizona State University for providing financial support without which this report could not have been completed. PREVIOUS INVESTIGATIONS Jones and Holl (1869) initially placed three newly established species, T. corpulenta, T. tuberosa, and T. v-scripta, in the genus Thlipsura. Jones (1887) established JT. angulata and T. plicata plus two varieties T. plicata var. uni- punctata and T. plicata var. bipunctata. Except for four species added to the genus by Krause (1891) and Kummerow (1924) the major contributions to Thlipsura since the work of Jones (1887) have been made by North American workers. Recently Abushik (1971) placed Russian forms described by Krandi- jevsky (1963) in Thlipsura. Table 1 is a list of all species known to us which have been described, illustrated and classified under Thlipsura. Several species which are legitimate members of TAlipsura but were originally placed in other genera have been added to the list. The table summarizes the nomenclatural history of these species from literature in which important taxonomic changes have been made. The taxonomic history of North American species placed in Thlipsura has been complex. An inconspicuous but significant contribution was made by Ulrich and Bassler (1923) when they reillustrated, by drawing, T. corpulenta. The illustration is erroneous to the extent that two posterior (considered an- terior by Ulrich and Bassler) furrows and one anterior pit are shown. The type figure of Jones and Holl (1869) shows one posterior furrow and no an- terior pit. Unfortunately, the erroneous illustration of Ulrich and Bassler (1923) Was perpetuated by Swartz (1932), and Bassler and Kellett (1934). The error was accentuated in illustrations by Kesling (1961) and Krandijevsky (1968). This error in illustrating ZT. corpulenta has had an important effect on the placement of North American species in TAlipsura. It prompted Swartz (1932) to conclude that T. corpulenta and T. furca Roth, 1929, are closely related. THLIPSURA JONES AND HoLi 89 The latter species has two posterior furrows (reentrants) and has been ade- quately illustrated by various authors (Roth, 1929; Swartz, 1932; Lundin, 1968; and Kesling, 1961 who mistakenly labeled it T. comfluens). Swartz (1932), in a revision of the Thlipsuridae, believed the posterior (anterior, according to Swartz) depressed area to be diagnostic, and accordingly placed five species and one variety in TAlipsura as indicated in Table 1. At the same time Swartz removed T. angulata, T. tuberosa, T. plicata, and its two varieties to a new genus, Thlipsurella. He divided the latter into five sections, one of which is entitled “Section of Thlipsurella plicata’. Division of Thlipsurella into five sections has prompted various authors (Swartz, 1932; Bassler and Kellett, 1934; Copeland, 1962; Lundin 1965 and 1968; and others) to place species in Thlipsurella which are only remotely related to T. ellipsoclefta Swartz, 1932, the type species. Thlipsurella has become something of a catch-all for a wide variety of forms, a situation which is complicated by the fact that the type species is represented only by molds and casts. Kesling’s (1961) illustration of 7. corpulenta served only to confirm the error of supposed similarity between it and T. furca. It is the least representa- tive of the various illustrations of ZT. corpulenta, a situation which is most unfortunate because of the impact the American Treatise has had as a reference on ostracodes. Krandijevsky (1968) attempted a revision of the Thlipsuridae. He, like others, apparently did not study specimens of Thlipsura corpulenta, and his diagnosis of the genus, as well as his illustration of the species, demonstrate that he too was under the illusion that T. corpulenta has two posterior furrows. Accordingly, he placed 7. furca, T. furcoides, T. subfurca and T. corpulenta in TAlipsura and added conditionally T. triloba (see Table 1). Also, Krandi- jevsky (1963) erected Thlipsohealdia in which he placed two species T. jonesi and T. binodosa. Abushik (1971) recognized the similarity of these species and placed them in synonymy. She further recognized their similarity to T. corpulenta and transferred Thlipsohealdia jonesi Krandijevsky, 1963 to Thlip- sura, thus invalidating Thlipsohealdia. We concur with Abushik (1971) on the basis of studying specimens of Thlipsura jonesi supplied by her. The most important contribution of Krandijevsky (1968) relative to North American species placed in Thlipsura is his new genus Neothlipsura. Unfortunately, he designated T. confluens Swartz, 1932, as the type species, a species which is represented only by external molds. We have studied the types and conclude on the basis of outline and general construction of the valves that Neothlipsura confluens (Swartz, 1932) is congeneric with several North American species formerly placed in Thlipsura. Krandijevsky (1968) has placed an inordinate emphasis on details of ornamentation. The shape of N. confluens suggests valve relationships and hinge arrangement identical to T. furcoides which, without question, is congeneric with JT. furca and T. primitiva. Accordingly, we believe the fol!owing species belong in Neothlipsura. N. robusta (Ulrich and Bassler, 1913) N. furca (Roth, 1929) N. primitiva (Roth, 1929) 90 R. F. Lunpin anp LEE E, PETERSEN . confluens (Swartz, 1932) . robusta var. tricornis (Swartz, 1932) . furcoides (Bassler, 1941) . thyridiotdes (Swartz and Swain, 1941) . subfurca (Polenova, 1958) . whiteavsi (Copeland, 1962) 4S = 22 S We should point out that N. subfurca (Polenova, 1958) is known to us only through the illustrations of Polenova (1958) and Polenova and Zanina (1960). Accordingly, this is a questionable assignment. Lundin (1968) indicated that T. robusta (Ulrich and Bassler, 1913) is not congeneric with Eucraterellina randolphi Wilson, 1935. If this is true, we see no reason at present for not placing the former species and T. robusta var. tricornis Swartz, 1932 in Neo- thlipsura. It is possible, however, that Neothlipsura will require emendation in the future, in which case these forms may be excluded from it. Adamezak (1967) emphasized the significance of the hinge and contact margin structures in defining the genus Silenis Neckaja, 1958 which Adamczak placed in the Thlipsuridae. According to Adamezak’s (1967) illustrations, however, it appears that the hinge in S. bass/eri is somewhat more complex than that of Thlipsura corpulenta and other Thlipsura species. Furthermore, Adam- czak’s photographs of S. bassleri suggest a more extensive contact groove than is shown in his drawings. T. corpulenta has neither the anterior and posterior hinge sockets nor the tongue-shaped projections of the right valve, as on S. bassleri (Adamezak, 1967, fig. 1). On the other hand, S§. bassleri ap- parently has a poorly developed contact groove along the posterior margin, posterior part of the ventral margin, and anterior margin of the left valve (see Adamezak, 1967, fig. 8A) much like that of T. corpulenta. Nevertheless, Adamezak’s contribution is an important one because it shows the basic construction of the Thlipsuracean hinge and contact margin structures. SPECIES REJECTED FROM THLIPSURA Table 1 lists those species which are herein rejected from Thlipsura. The hinge, contact margin, and general morphology of Thlipsura are des- cribed below. The following discussion is a justification for removal of the various species from Thlipsura. Adamezak (1967) has shown TAlipsurella? discreta to have a well- developed complete contact groove in the left valve. The same is true for T? v-scripta. Furthermore, the surface morphology of these species easily dis- tinguishes them from Thlipsura. We have not studied specimens of the species erected by Krause (1891) and Kummerow (1924). Published illustrations of these, however, indicate that they do not belong to TAlipsura on the basis of outline and surface morphology. T. multipunctata (Pl. 4, figs. 4-7) clearly belongs to Thlipsurella. It is closely related to T. cllipsoclefta, Swartz, 1932, the type species. We have not presently studied Neothlipsura robusta (Ulrich and Bassler, 1913) or N. robusta var. tricornis (Swartz, 1932). Lundin (1968), however, ; . oe eek b Bie yns bein t CALE, PEM: Web IEe) ie it - _— A _ Table 1. Nomenclatvral history of species placed in Thlipsura. raterellina robusta Ulrich & Bassler, 1913 Thlipsura angulata Jones, 1887 Thlipsura confluens Swartz, 1932 : Thlipsura corpulenta Jones & Holl, 1869 hlipsura curvistriata Roth, 1929 hlipsura fossata Roth, 1929 hlipsura furca Roth, 1929 lipsura furcoides Bassler, 1941 hlipsura n. sp. hlipsura muricurva Roth, 1929 hlipsura parallela Roth, 1929 hlipsura personata Krause, 1891 hlipsura plicata Jones, 1887 hnlipsura plicata bipunctata Jones, hlipsura plicata unipunctata Jones, hlipsura primitiva Roth, 1929 hnlipsura robusta tricornis Swartz, 1932 hnlipsura simplex Krause, 1891 nlipsura striatopunctata Roth, 1929 hlipsura subfurca Polenova, 1958 nlipsura tetragona Krause, 1891 Thlipsura thyridioides Swartz & Swain, 1941 hlipsura triloba Kummerow, 1924 nlipsura tuberosa Jones & Holl, 1869 hlipsura v-scripta Jones & Holl, 1869 nlipsura v-scripta discreta Jones, 1887 ipsura whiteavesi Copeland, 1962 psohealdia binodosa Krandijevsky, 1963 ohealdia jonesi Krandijevsky, 1963 urella? sp. A Lundin & Newton, 1970 fella? sp. B Lundin & Newton, 1970 1887 1887 ; ; ; : : . . : . ; . ; . : ' : ' . . ' ; ; ; hlipsura multipunctata Ulrich & Bassler, 1913 Swartz, 1932 Thlipsura Thlipsurella Thlipsura Thlipsura Thlipsure lla Thlipsurella Thlipsura Thlipsurella Thlipsurella Thlipsurella Thlipsurella? Thlipsurella Thlipsurella ThlipsSurella Thlipsura Thlipsura Thlipsurella? ThlipSurella Thlipsurella? Re jected ThlipS8urella Thlips8urella Thlipsurella 4 > , Kellett, Bassler and 1934 Thlipsura Thlipsurella Thlipsura Thlipsura Thlipsurella Thlipsurella Thlipsura Thlipsurella Thlipsurelia Thlipsurella Thlipsurella? Thlipsurella Thlipsurella Thlipsurella Thlipsura Thlipsura Octonaria Thlipsurella Thlipsurella Thlipsura Thlipsurella Thlipsurella Thlipsurella Krandi jevsky Lundin, 1965 Lundin, 1968 1968 Abushik, 1971 | This report Thlipsurella? Thlipsuroides Healdia Thlipsuroides Thlipsurella? Thlipsura Thlipsurella? Craterellina Euthlipsurella Neothlipsura Thlipsura Euthlipsurella Euthlipsurella Thlipsura Thlipsura Thlipsurella Euthlipsurella Rothellina Krausellina Euthlipsurella Euthlipsurella Euthlipsurella Thlipsohealdia Craterellina Krausellina Rothellina Thlipsura Krausellina Neothlipsura Thlipsura? Euthlipsurella Thlipsurella Thlipsurella Thlipsohealdia Thlipsohealdia Thlipsura Thlipsura Thlipsura Neothlipsura Thlipsura Neothlipsura Thlipsura Re jected Rejected Neothlipsura Neothlipsura Thlipsura Thlipsurella Re jected Thlipsuroides Re jected Thlipsura Thlipsura Thlipsura Neothlipsura Neothlipsura Re jected Thlipsuroides Neothlipsura? Re jected Neothlipsura Re jected Thlipsura Thlipsurella? Thlipsurella? Neothlipsura Thlipsura Thlipsura Thlipsura? Thlipsura THLIPSURA JONES AND HoLi 91 studied the types of the former species and they certainly do not belong to Thlipsura, Furthermore, we doubt that N. robusta is congeneric with Eucrater- ellina randolphi Wilson, 1935 (see Lundin, 1968). N. robusta var. tricornis (Swartz, 1932) is very similar to N. robusta hence the same generic designa- tion. The posterior nodes on forms like N. robusta and N. robusta var. tricornis probably formed through fusion of the complex posterior furrows of N. confluens. N. furca (Roth, 1929), Pl. 3, figs. 4-7, NM. furcoides (Bassler, 1941), Pl. 4, figs. 10-13, and N. primitiva (Roth, 1929), Pl. 4, figs. 1-3, have an uninterrupted contact groove in the left valve although it is poorly developed along the mid-venter of the latter species. These species are placed in Neothlip- sura on the basis of their similar outline and morphology to N. confluens (Swartz, 1932) the type species of the genus. The latter similarity justifies placement of N. thyridioides (Swartz and Swain, 1941), Pl. 4, fig. 8, and N. whiteavsi (Copeland, 1962), Pl. 4, fig. 9, in the same genus. Illustrations of T. subfurca Polenova, 1958, show that it does not belong to Thlipsura but probably Neothlipsura. The hinge structure of T. fossata (PI. 2, figs. 3, 4) is basically like that of T. corpulenta, but the orientation of the hinge and the carapace morphology are distinctly different. Accordingly, T. fossata, T. muricurva, and T. curvis- triata are removed from Thlipsura. Krandijevsky (1968), placed these species in a new genus, Euthlipsurella. That genus is, however, invalid because it is based on T. flicata Jones, 1887, which is a synonym of T. corpulenta Jones and Holl, 1869. Accordingly, the species discussed above most probably belong in a new genus along with several other species. The hingement of Thlipsuroides Morris and Hill, 1952, has not been adequately studied. A few specimens of TJ. thlipsuroides Morris and Hill, 1952 in our collections from the Newsom (Waldron) Shale (Silurian) and the Brownsport Formation (Silurian) have a hinge and hinge orientation which is like that of Thlipsura, as far as can be determined from the material available for study. Thlipsuroides can be distinguished from Thlipsura on other grounds, however. Thlipsuroides species have two distinct horizontal pitted furrows which are terminated by a posterior ridge. Accordingly, the morphology of the posterior portion of the shell is distinctly different from that of Thlipsura. Therefore, T. parallela Roth, 1929 and T. striatopunctata Roth, 1929 are placed in Thlipsuroides. SYSTEMATIC SECTION Family THLIPSURIDAE Genus THLIPSURA Jones and Holl, 1869 1869. Thlipsura (part), Jones and Holl, Ann. Mag. Nat. Hist., ser. 4, vol. 3, No. 15, pp. 213-14, pl. 15, figs. 1-2. 1887. Thlipsura Jones and Holl, (part) Jones, Aun. Mag. Nat. Hist., ser. 5 vol. 19, No. 114, pp. 400-403, pl. 12, figs. 9-13. ’ 92 R. F. Lunpin anp LEE E, PETERSEN 1923. Thlipsura Jones and Holl, (part) Ulrich and Bassler, Maryland Geol. Sur., Silurian volume, p. 317, fig. 23, No. 6. 1932. Thlipsura Jones and Holl, (part) Swartz, Jour. Paleont., vol. 6, pp. 38-39, pl. 10, fig. 1. 1932. Thlipsurella (part) Swartz, idem, pp. 44-45. 1934. Thlipsura Jones and Holl, (part) Bassler and Kellett, Geol. Soc. Amer., Spec. Paper, No. 1, pp. 36, 483-487, fig. 16, No. 6. 1934. Thlipsurella Swartz, (part) Bassler and Kellett, zdem, pp. 485-487. 1961. Thlipsura Jones and Holl, (part) Kesling, Treatise on Invertebrate Paleontology, part Q, Arthropoda 3, Geol. Soc. Amer., pp. 378, fig. 304, No. 2d. 1963. Thlipsohealdia Krandijevsky, Akad. Nauk Ukr. SSR, Inst. Geol. Nauk, ops GE oases TS, Is. 1968. Thlipsura (part) Krandijevsky, Akad. Nauk. Ukr. SSR, Inst. Geol. Nataikeipn 67ple: dele hicats 1968. Thlipsohealdia (part) Krandijevsky, idem, pp. 67-68. 1968. Euthlipsurella (part) Krandijevsky, idem, pp. 71-72. 1970. Thlipsurella? Swartz, Lundin and Newton, Geol. Sur. Alabama, Bull. No. 95, pp. 44-45, pl. 6, fig. 4, pl. 7, fig. 2. 1971. Thlipsura Jones and Holl, Abushik, Academy of Science, USSR, “Nauka”, Moscow, pp. 114-116, pl. 41, figs. 1-8, pl. 42, figs. 1-2. Tybe species. — Thlipsura corpulenta Jones and Holl, Silurian, England. Diagnosis. — Shell subreniform in lateral view with poorly-to well-devel- oped straight, curved or sinuate furrow extending anteriorly between two horizontal lobes from near the posterior border. Left valve larger than right and overlapping it along free border. Surface smooth. Hinge straight, inclined consisting of groove in right valve and list in left valve. Groove anterior and posterior to hinge list merges with poorly developed contact groove which disappears ventrally. Stop-ridges poorly developed or absent. Species composition. — The following species are here placed in Thlipsura. Thiipsura corpulenta Jones and Holl, 1869 Thlipsohealdia jonesi Krandijevsky, 1963 = T. binodosa Krandijevsky, 1963 ?Thlipsurclla? sp. A Lundin and Newton, 1970 Thlipsurella? sp. B Lundin and Newton, 1970 Thlipsura, n. sp. Remarks.— We consider the hinge structure and orientation (inclined to longitudinal axis of the valve, Adamezak, 1966, p. 13) and the contact margin structure to be critical in the definition of the genus. The contact groove disappears along the midventral border and is best developed along the posterior border but is nowhere deep. The surface morphology of the posterior portion of the valves in all species consists of a depressed area (furrow) with a horizontal lobe above and below. Thlipsurella? sp. A Lundin and Newton (1970) is questionably placed in THLipsuRA JONES AND HoLi 93 Thlipsura because material available for study is inadequate to clearly define the contact margin structures. One left valve in our collection, however, has a hinge like that of T. corpulenta. Occurrence. — Silurian of Europe and North America. Thlipsura corpulenta Jones and Holl Pl. 1, figs. 1-19; Pl. 2, figs. 1, 2; Pl. 3, figs. 8-14; Text-fig. 1 1869. Thlipsura corpulenta Jones and Holl, Ann. Mag. Nat. Hist., ser. 4, vol. 3, No. 15, p. 214, pl. 15, fig. 1. 1869. Thlipsura tuberosa Jones and Holl, idem., p. 214, pl. 15, fig. 2. 1887. Thlipsura angulata Jones, Ann. Mag. Nat. Hist., ser. 5, vol. 19, No. 114, p. 402, pl. 12, fig. 9. 1887. Thlipsura plicata Jones, idem., p. 402, pl. 12, fig. 10. 1887. Thlipsura plicata var. unipunctata Jones, idem., p. 403, pl. 12, figs. 11-12. 1887. Thlipsura .plicata var. bipunctata Jones, idem., p. 403, ok, WI, sHieg IIe 1923. Thlipsura corpulenta Jones and Holl, Ulrich and Bassler, Maryland Geol. Sur., Silurian volume, p. 317, fig. 23, No. 6. 1932. Thlipsura corpulenta Jones and Holl, Swartz, Jour. Paleont. vol. 6, pe 35) ple lOy dig. 16 1934. Thlipsura corpulenta Jones and Holl, Bassler and Kellett, Geol. Soc. Amer., Special Paper, No. 1, p. 36, 483, fig. 16, No. 6. 1961. Thlipsura corpulenta Jones and Holl, Kesling, Treatise on Invertebrate Paleontology, part Q, Arthropoda 3, Geol. Soc. Amer., p. 378, fig. 304, No. 2d. 1968. Thlipsura corpulenta Jones and Holl, Krandijevsky, Akad. Nauk. Ukr. SSR, Inst. Geol. Nauk, p. 67, pl. 11, fig. 1. 1971. Thlipsura corpulenta Jones and Holl, Abushik, Academy of Science, USSR, “Nauka”, Moscow, p. 115, pl. 42, figs. 1-2. Lectotype. —B.M.N.H. I 2059, pl. 1, figs. 16-19. Type locality and stratum.— Woolhope beds (Wenlockian) near Malvern, Worcestershire, England. Diagnosis. — Species of Thlipsura with straight to curved (concave dor- sally) posterior furrow between two (dorsal and ventral) horizontal lobes which are moderately well to well developed. Pit at midheight anterior to midlength may be present. Position of adductor muscle marked by circular depression on interior surface. Hinge and contact margin as for genus. Surface smooth. Description. — The carapace is subreniform in lateral view, subelliptical in dorsal and ventral views and subquadrate in end view. The dorsal border of the left valve is evenly convex to slightly angulate, that of the right valve more distinctly angulate. The anterior and posterior borders of the left valve and the anterior border of the right valve are sharply rounded whereas the posterior border of the right valve is sharply rounded to angulate. The ventral border of the left valve is slightly convex to straight, that of the right valve is slightly sinuate. The greatest height is at or slightly behind midlength, the greatest length is just below midheight, and the greatest width is medial. The valves are unequal, the left overlapping the right along the entire R. F. Lunpin anp Lee E, PETERSEN 94 *(LES-SIN ‘ON 2[dues) sempying Je U1aAag JaATY ay) Suoje spoq SEMP[INg oy} Woz (s}op) ‘ds ‘U ‘vunsgijyT puke (6ZS-SW ‘ON a[dues) SUIOA[EJA, FY} JO aUO}SAUNIT YOO[UIAA FY} WoOIZ (Sa[suLII3) [JOY pue sauof pjuajng4102 vansdijy J, JO SaA[CA Ifa] JO WeAeIp UOIsIadsIpP azIg “[ “BI-3x9 7, cil vil el Zl UL OL 6 ww ‘yp,suay ee ee wv Vv ® Vv e® @80@ e@ @ @@ee@0 Vv @ e Vv e e e Vv yVvYy eee v VwV Vv eee VwvvVvyv ee e@ @ SvvVwVvVv Vv ww ‘yysiay THLIpsuRA Jones AND HoLi o5 free border. The surface of the valves is smooth. The posterior portion of the valves is depressed. From a position of midheight at the posterior end of the valve the depression extends anterodorsally forming a furrow between two horizontal lobes. The latter merge anteriorly with the general surface of the valves. The furrow is variable in length, depth, and shape. On some specimens a weak dorsoventrally elongate depression is present at midheight anterior to midlength. Generally it is poorly developed and it is absent from most speci- mens. The hinge consists of an inclined, straight, simple groove in the right valve and a straight list on the left valve. A groove (socket) occurs at either end of the list which merges with a poorly developed contact groove. Posteriorly the contact groove extends from the posterior end of the hinge to the posterior portion of the ventral margin. The contact groove is poorly developed or absent along the anteroventral margin but is present from about midheight of the anterior margin to the anterior end of the hinge. On one specimen (Pl. 3, fig. 11) the grooves at either end of the hinge nearly merge to split the hinge list. A circular depression which represents the position of the adductor muscle attachment is present on the interior surface of the valve (Pl. 3, fig. 13). It is anterior to midlength at midheight. Muscle scars are unknown. Variation,— Size variation in T. corpulenta for a population from the Malverns, England, is shown in Text-figure 1. Other recognizable variation concerns the development, shape, and length of the posterior furrow and associated horizontal lobes, and the development of the anterior depression. Jones and Holl recognized variation in these features in 1869. The posterior furrow may be weak or strong but in all cases it is clearly recognizable. It may be essentially straight or it may be curved (concave dorsally). It may be short or long. On some specimens it does not reach midlength (PI. 1, fig. 3), on others it extends slightly beyond midlength (PI. 1, fig. 2). The furrow is inclined in an anterodorsal-posteroventral direction on all specimens. The angle of inclination to a line tangent to the ventral border, however, varies from four degrees to thirty degrees in a population from Lincoln Hill, England. This variation in depth, shape, length, and orientation of the furrow has a corresponding influence on the same characteristics of the adjacent horizontal lobes. The anterior depression is generally absent but it is poorly developed on a small proportion of specimens of the populations studied. We have seen it distinctly developed on only one specimen (PI. 1, fig. 15). Ontogeny.— Immature specimens are rare in our collections and probably represent only instars II and III (the adults being designated instar I). Those juveniles available for study shown no significant morphological differences from the adults except for their smaller size and corresponding reduction in development of the posterior furrow. It is likely that the furrow and horizontal lobes would be absent from the earlier instars of this species, but we have no specimens to demonstrate this. Remarks.— T. tuberosa is based on an internal mold of JT. corpulenta, 96 R. F. Lunpin anno LEE E, PETERSEN The node on the former form is nothing more than a reflection of the interior circular depression described above (PI. 2, figs. 1, 2). T. angulata, T. plicata, and T. plicata var. unipunctata are based on minor variants of T. corpulenta (see discussion of variation above). Variants of these kinds are present in numerous populations from the Wenlockian of England. T. flicata var. bipunctata is based on a damaged specimen. It is not “bipunctate” as photo- graphs of the type specimen, B.M.N.H. In 52413, show (PI. 1, figs. 8, 9). Accordingly, all of these species and varieties are here placed in synonymy with T. corpulenta. This has obvious effects on previous taxonomic revisions of the Thlipsuridae. For example, Swartz’s (1932) “Section of Thlipsurella plicata” and Krandijevsky’s (1968) genus Euthlipsurella are meaningless, because both are based on T. plicata. Specimens designated as the type specimens for T. corpulenta, T. angu- lata, T. plicata and T. plicata var. bipunctata in the coilections of the British Museum of Natural History are illustrated on Plate 1. Materials studied.—In addition to the type specimens, thousands of specimens from numerous Wenlockian localities of England have been studied. Preservation varies from poor to excellent but generally is good. Thlipsura, n. sp. Pl. 2, figs. 5-14; Text-fig. 1 Holotype. — ASU X-15, Pl. 2, figs. 7, 8. Locality and stratum.— Buildwas beds (Wenlockian) along River Severn near Buildwas, England (National Grid Reference No. SJ 6435/0450). Diagnosis. — Species of Thlipsura on which the posterior furrow is well developed, straight to sinuate (never concave dorsally) and generally short. Ventral horizontal lobe longer than dorsal horizontal lobe. Dorsal horizontal lobe forms posterodorsal border. Remarks.— This species has been recognized only from the Buildwas beds (Wenlockian) of England, and has not been found associated with T. corpulenta. Material studied. — Hundreds of specimens (all carapaces) have been studied. Preservation varies from good to excellent. REPOSITORIES All specimens illustrated in this report are deposited in the collections of the British Museum of Natural History (B.M.N.H.), United States National Museum of Natural History (U.S.N.M.), Geological Survey of Canada (G.S.C.), Pennsylvania State University (P.S.U.), or Arizona State University (A.S.U.). REFERENCES CITED Abushik, A. F. 1971. Paleozoic ostracodes of the European part of the Russian Platform. Academy of Science, USSR, “Nauka”, Moscow, pp. 1-248, 58 pls. (in Russian). Adamczak, F. 1966. On kloedenellids and cytherellids (Ostracoda, Platycopa) from the Silurian of Gotland. Stockholm Contr. Geology, vol. 15, pp. 7-21, 5 pls., 7 text-figs. THLIPSURA JoNES AND Ho. 97 1967. Morphology of two Silurian metacope ostracodes from Gotland. Geologiska Foéreningens i Stockholm Férhandlingar, vol. 88, pp. 462-475, 12 text-figs. Bassler, R. S. 1941. Ostracoda from the Devonian (Onondaga) chert of western Ten- nessec. Washington Acad. Science, Jour., vol. 31, pp. 21-27, 37 figs. Bassler, R. S., and Kellett, B. 1934. Bibliographic index of Paleozoic Ostracoda. Geol. Soc. America, Spec. Paper 1, 500 pp., 24 text-figs. Copeland, M. J. 1962. Canadian fossil Ostracoda, Conchostraca, and Phyllocarida. Can- ada Geol. Sur., Bull. 91, 57 pp., 12 pls., 2 text-figs. Jones, T. R. 1887. Notes on the Paleozoic bivalved Entomostraca. No. XXIV. On some Silurian genera and species (continued). Ann. Mag. Nat. Hist., ser. 5, vol. 19, pp. 400-416, pls. 12, 13. Jones, T. R., and Holl, H. B. 1869. Notes on the Paleozoic Entomostraca. No. IX. Some Silurian spec- ies. Ann. Mag. Nat. Hist., ser. 4, vol. 3, pp. 211-229, pls. 14, 15, text-figs. 1-7. Kesling, R. V. 1961. Family Thlipsuridae. Pp. Q377-Q380, text-figs. 304-307, in Ben- son, R. H., and others. Arthropoda 3. Part Q, Treatise on Inver- tebrate Paleontology (R. C. Moore, Editor), Univ. Kansas Press and Geol. Soc. America. Krandijevsky, V. S. 1963. Fauna ostrakod silurijskich vidkladiv Podillia. Akad. Nauk. Ukr. SSR, Inst. Geol. Nauk, pp. 1-149 (in Russian). 1968. Revision of the Family Thlipsuridae Ulrich (Ostracoda). Pp. 63- 79, pl. 11, 72 Krandijevsky, V. S., Ishchenko, T. A., Kiryanov, V. V. Paleontology and straigraphy of the lower Paleozoic of Volyn-Podolia, Acad. Nauk Ukr. SSR, Inst. Geol. Nauk (in Rus- sian). Krause, A. 1891. Beitrag zur Kenninis der ostrakoden-Fauna in Silurischen Di- luvialgeschicben, Deutsch. Geol. Ges. Zeitschr., vol. 43, No. 2, pp. 488-529. Kummerow, E. 1924. Beitrage zur Kenntnis der Ostracoden und Phyllocariden aus nor- dischen Diluvialgeschieben. Preuss. Geol. Landesanst., Jahrb., vol. 44, pp. 405-448. Lundin, R. F. 1965. Ostracodes of the Henryhouse Formation (Silurian) in Oklahoma. Oklahoma Geol. Sur., Bull. 108, 104 pp., 18 pls., 45 text-figs. 1968. Ostracodes of the Haragan Formation (Devonian) of Oklahoma, Oklahoma Geol. Sur., Bull. 116, 121 pp., 22 pls., 51 text-figs. Lundin, R. F., and Newton, G. D. 1970. Ostracoda and the Silurian stratigraphy of Northwestern Ala- bama. Alabama Geol. Sur., Bull. 95, 51 pp., 7 pls., 6 text-figs, Morris, R. W., and Hill, B. L., Jr. 1952. New Ostracoda from the middle Silurian Newsom Shale of Ten- nessee. Bull. Amer. Paleont., vol. 34, pp. 131-148, pls. 9, 10. Neckaja, A. I. 1958. Nowye wvidy i rody ostrakod ordovika i Silura Severo-Zapada Russkoi platformy, in Voprosy sistematiki i opisanie novykh widow, < 98 R. F. Lunpin anp Lee E. PETERSEN rodov i podsemeistv Foraminifer i ostrakod, sbornik 1X of Micro- fauna SSSR. Vses. Neft. Nauchno-Issled Geol.-Razved. Inst. (VNIGRI), Trudy, new ser., No. 115, pp. 349-373, 3 pls. (in Rus- sian). Polenova, E. N. 1958. New genera and species of Ostracoda, p. 261, pl. 3, figs. 6a, b, in Abushik, A.F., and others. Microfauna SSR, vol. 9, All-Union Sci.-Res. Geol.-Prosp. Petrol. Inst. (VNIGRI), new series, No. 115, pp. 232-287, pls. 1-6 (in Russian). Polenova, E. N., and Zaninia, I. E. 1960. Superfamily Thlipsuridacea. Pp. 334-336, text-figs. 847-854, in Zanina, I. E., Polenova, E. N., and others. Volume VIII, Arthro- poda, Trilobitomorpha and Crustacea. Foundations of Paleon- tology USSR. Handbook for paleontologists and geologist USSR, Moscow (in Russian). Roth, R. I. 1929. Some ostracodes from the Haragan Marl, Devonian, of Oklahoma. Jour. Paleont., vol. 3, pp. 327-372, 4 pls. Swartz, F. M. 1932. Revision of the ostracode family Thlipsuridae, with descriptions of new species from the lower Devonian of Pennsylvania. Jour. Paleont., vol. 6, pp. 36-58, pls. 10, 11. Swartz, F. M., and Swain, F. M. 1941. Ostracodes of the Middle Devonian Onondaga beds of central Pennsylvania. Geol. Soc. America, Bull., vol. 52, pp. 381-457, pls. 1-8, 2 text-figs. Ulrich, E. O. 1894. The lower Silurian Ostracoda of Minnesota. Pp. 629-693, pls. 43- 46, text-figs. 46-52, im Ulrich, E. O. and others. The geology of Minnesota. Minnesota Geol. Nat. Hist. Sur., Rept., vol. 3, pt. 2. Ulrich, E. O., and Bassler, R. S. 1913. Ostracoda, Pp. 513-542, pls. 95-98, 12 Swartz, C. K., and others. Systematic paleontology of the lower Devonian deposits of Mary- land, Maryland Geol. Sur., Lower Devonian volume. 1923. Paleozoic Ostracoda: Their morphology, classification and occur- rence. Pp. 271-391, text-figs. 11-26, in Swartz, C. K., and others. Maryland Geol. Sur., Silurian volume. Wilson, C. W., Jr. 1935. The ostracode fauna of the Birdsong Shale, Helderberg, of western Tennessee. Jour. Paleont., vol. 9, pp. 627-646, pls. 77-78. Robert F. Lundin and Lee E. Petersen Department of Geology Arizona State U. Tempe, Arizona 85281 DISCUSSION Dr. F. M. Swartz: I was very pleased to have this paper read. It provides another example of the value of reillustration of type examples of a classical species. THLIPSURA JONES AND Hoi. ee ADDENDUM During preparation of this paper we were not aware of the work of Gailite (1967)*. In this paper she has placed Thlipsura simplex Krause, 1891 and T. personata Krause, 1891 in a new genus Scaldianella Gailite, 1967. She established another new genus, Hebellum Gailit2, 1967, in which she placed T. tetragona Krause, 1891. Table 1 shows that Krandijevsky (1968) placed all of these species in Krausellina Krandijevsky, 1968. Gailite (1967) described two new species JT. /ubrica Gailite, 1967 and T. panda Gailite, 1967. We are familiar with these species only through Gailite’s (1967) illustrations but agree that both are species of Thlipsura. *Gailite, L. K. 1967. Opisanie ostrakod. Pp. 89-168, pls. 1-13, in Gailite, L. K., Pybni- kova, M. B., and Ulste, P.Zh. Stratigrafiya, fauna i uslowiya obrazovaniya silurijskikh porod srednej Pribaltiki, Isdatel’stuv “Zinatne”, Riga, (in Russian). 100 Figure 1-19. Thlipsura corpulenta Jones and Holl R. F. Lunpin anp Lee E, PETERSEN EXPLANATION OF PLATE 1 (All figures x 30) Reece eee ene e eee e seen eee e etna tees eeee eee 1-3, 5-6. Right lateral views of adult carapaces showing variations in surface morphology. Wenlock Limestone, Lincoln Hill, England. A.S.U. X-24, X-25, K-22, X-21, X-23. 4, 7. Right lateral views of two adult carapaces. Wenlock Limestone, Much Wenlock, England. A.S.U. X-26, X-27. 8-9. Left lateral and right lateral views of type specimen of Thlipsura plicata var. bipunctata Jones. Shales over Wenlock Limestone, England. BMNH In 52413. 10-12. Right lateral view of carapace, lateral view of left valve, and left lateral view of carapace of type specimens of Thlipsura angulata Jones. Shales over Wenlock Limestone, England. BMNH JI 1923. 13-14. Right lateral and left lateral views of carapace of type specimen of Thlipsura plicata Jones. Shales over Wenlock Limestone, England. BMNH IN 52410. 15. Lateral view of left valve showing well-developed anterior depression. Woolhope beds, near Malvern, England. BMNH I 2077. 16-19. Lectotype. Dorsal, left lateral, right lateral, and ventral views of type specimen. Woolhope beds, near Malvern, England. BMNH I 2059. Plate 1 THLIPSURA JONES AND HoLyi 101 102 R. F. Lunpin ann Lee E, PETERSEN EXPLANATION OF PLATE 2 (All figures x 30 unless designated) Figure Page 1-2. Thlipsura corpulenta Jones and Holl .22:......2.2.2.02- 93 Left lateral and right lateral views of adult carapace identi- fied as Thlipsura tuberosa Jones and Holl. Outer shell of left valve has been removed exposing internal mold. Node is reflec- tion of the interior depression. England. BMNH I 1925. 3-4. “Thlipsurella” fossata (Roth) Interior views of adult right valve and adult left valve show- ing hinge and orientation of hinge. * 24. Haragan Formation (Devonian), Oklahoma. ASU X-18, X-17. 5-14, Thlipsura, Th. SP. siccciiccicecss-cescvetecestroedent cs Ee eee 95 5. Right lateral view of instar III carapace. 6. Left lateral view of instar II carapace. 7-8. Right lateral and left lateral views of adult carapace. 9. Left lateral view of adult carapace. 10-12. Left lateral, right lateral, and dorsal views of adult carapace. 13-14. Ventral and right lateral views of adult carapace. Buildwas beds, along River Severn, Buildwas, Shropshire, England. ASU X-20, X-19, X-15, K-16, K-13, K-14. THLIPSURA JONES AND Hoty 103 Plate 2 104 Figure R. F. Lunpin anp Lee E, PETERSEN EXPLANATION OF PLATE 3 (All figures x 40) 1-3. Thlipsura sp. B (Lundin and Newton) .................:c.:c.csscssccssesssenes 1. Oblique interior view of adult left valve. Posterior portion of hinge list is broken. 2. Right lateral view of of adult cara- pace. 3. Interior view of adult right valve. Brownsport Forma- tion (Silurian), Tennessee. ASU X-12, X-10, X-11. 4-7. Neothlipsura furca (Roth)) 22... ee 4-5. Right lateral and interior views of adult right valve. Note hinge groove and contact list. 6. Interior view of adult left valve showing hinge list and contact groove. 7. Oblique interior view of adult left valve showing contact groove along venter. Birdsong Formation (Devonian), Tennessee. ASU X-9, X-8, X-7. 8-14. Thlipsura corpulenta Jones and Holl ...00.0........0ccceeceeeeeesereeee 8-10. Matrix obscures posterior portion of figure 8. Interior views of adult right valves showing hinge groove. 11. Oblique interior view of adult left valve showing merging of grooves at posterior and anterior ends of hinge nearly splitting the hinge list. 12. Oblique interior view of adult left valve showing poorly developed posterior stop ridge. 13-14. Oblique interior and in- terior views of adult left valve. Oblique view shows interior depression marking position of adductor muscle. Interior view shows hinge list. Note weak contact groove. Wenlock Limestone, Lincoln Hill, England. A.S.U. X-6, X-5, X-3, X-2, X-4, X-1. Plate 3 THLIPSURA JONES AND Hoy 106 Figure 1-3. 47. 10-13. 14-15. R. F. Lunpin anp LEE E. PETERSEN EXPLANATION OF PLATE 4 (All figures x 40 unless designated) Neothlipsura. primitiva (Roth) ........:......5.02.:00e eee Interior view of adult left valve showing hinge list and con- tact groove and right lateral and oblique interior view of adult right valve. Note hinge groove on right valve. X 48. Henry- house Formation (Silurian), Oklahoma. ASU X-29, X-28. Thlipsurella multipunctata (Ulrich and Bassler) ...............0........ Holotype. Right lateral, left lateral, ventral and dorsal views of adult carapace. Lower Oriskany, West Virginia. USNM 53381. Neothlipsura thyridioides (Swartz and Swain) .....................00. Holotype. Right lateral view of external mold of adult right valve. Onondaga beds, West Virginia. PSU 108-2. Neothlipsura whiteavesi (Copeland) .................ccccccccceecceeeeeeeceeeees Holotype. Right lateral view of adult carapace. Dalhousie beds, New Brunswick. GSC 14519. Neothlipsura furcoides (Bassler) .............00c0ccccccccccceccceeeseeseteceeeeeeees 10, 11, 13. Interior, oblique interior, and left lateral views of adult left valve. Note hinge list and uninterrupted contact groove. Hinge list is chipped. 12. Interior view of adult right valve showing hinge groove and contact list. x 32. Camden Formation, Tennessee. USNM 101035. Neothlipsura confluens (Swartz) -.......¢...:...0.0.0.- eee Photographical replica of external molds of adult left and right valves. Photographs are prints of positive slides made from negatives of the molds. x 32. Shriver Chert, Pennsyl- vania. USNM 86495. Plate 4 THLIPSURA JONES AND HoLi QUANTITATIVE ANALYSIS OF DIMORPHISM IN CARBONITA HUMILIS (JONES AND KIRKBY) Martin J. M. Biess Geological Bureau Heerlen, Netherlands and Joun E. Potiarp University of Manchester, England ABSTRACT Carbonita humilis (Jones and Kirkby) is a non-marine ostracode, occurring throughout the Westphalian of Western Europe, the Pennsylvanian of the United States, and the Upper Carboniferous of the Maritime Provinces of Canada. In 1966 Pollard postulated sexual dimorphism for this species, distinguish- ing males and females by differences in H/L-ratios, lateral and dorsal outlines. A quantitative study of two populations of C. humilis (one from the Upper Westphalian A of The Netherlands, and one from the Lower Westphalian C of Great Britain) shows that adult specimens may be differentiated according to sex by using dorsal outline, H/L-ratios and W/L ratios in some cases. However, variability of each sex may be greater than the average difference between them. These facts, when considered in the light of published work on Recent ostracodes, pose the question as to whether reproduction in C. humilis Was syngamic, parthenogenetic, or variable depending on environment. ZUSAMMENFASSUNG Carbonita humilis (Jones und Kirkby) ist ein Siisswasserostracode, der im Westfal Westeuropas, im Pennsylvanian der Vereinigte Staaten, und im Ober- karbon Kanadas vorkommt. Im 1966 wurde von Pollard Sexualdimorphismus in dieser Art nachge- wiesen. Er fand mannliche und weibliche Individuen mit unterschiedlichen H/L-Ratio und Dorsalumriss. Ein quantitatives Studium von zwei Populationen von C. humilis — eine aus dem Oberwestfal A der Niederlanden, die andere aus dem Unterwestfal C Grossbritanniens — hat gezeigt, dass adulte Mannchen und Weibchen sich voneinander unterscheiden kénnen durch ihre Dorsal- und Seitenumriss, und durch ihre H/L- und W/L-Ratios. Die Variabilitat innerhalb einer Dimorph kann aber grésser sein als der mittlere Unterschied zwischen den zwei Dimor- phen. Diese Tatsachen rufen die Frage auf — vor allem wenn man die Arbeiten liber rezente Ostracoden besieht — ob die Fortpflanzung in C. humilis syngam, parthenogenetisch oder variabel (abhangig der Fazies) war. INTRODUCTION Carbonita humilis (Jones and Kirkby, 1879) is one of the most common and widespread non-marine ostracodes from the Upper Carboniferous. This species has been recognized in Westphalian sediments of Great Britain, France, Belgium, The Netherlands, Germany, and Spain but is also known from Pennsylvanian strata of the United States and the Upper Carboniferous of the Maritime Provinces of Canada. It is a medium-sized, subovate ostracode of variable size and outline. Because of this often not recognized variation, several “species” have been erected in the course of the past 90 years, which were distinguished by slightly different shape and dimensions. The discovery of two ostracode bands with abundant and relatively well-preserved specimens from 110 M. J. M. Buess anv J. E. Pottarp the Westphalian of Great Britain and The Netherlands has enabled the authors to study the variation within this species (Bless and Pollard, 1972). It has been shown that the variation of the lateral outline can best be expressed by using three parameters: H/L-ratio, degree of arching of the dorsum and rela- tive position of maximum height. Also the dorsal outline is variable. This is shown by examination of the W/L-ratio and relative position of maximum width. Pollard (1966) postulated sexual dimorphism in this species. He distinguish- ed males and females by means of H/L-ratio and dorsal and lateral outline. Dimorphism was also postulated for Carbonita inflata by Anderson (1970), but we are still not sure if this latter species should be included as an extreme variant in C. Aumilis. According to Pollard and Anderson, sexual dimorphism in Carbonita is of domiciliar type, one dimorph being distinguished from the other by a more swollen posterior part of the carapace. Indeed, many specimens in any studied assemblage of C. humilis show this in dorsal view convincingly. On the other hand, qualitative studies do not show always a direct relationship between the different dorsal shape and the H/L-ratio or lateral shape. The present report contains a quantitative analysis of the possible relationship be- tween these characters by means of pictographs, graphs, and statistical analysis of measurements. Only univarate statistics have been applied because our study was confined to adult specimens. The following abbreviations are used for statistical para- meters in this report: N (Number of specimens measured), i (mean length), H (mean height), Ww (mean width) Vv (mean volume, approximated as the product of %xLxHxW), H/L (mean height/length ratio), W/L (mean width/ length ratio), OR (observed range for the length), S (standard deviation of length), S (standard deviation of height), v (variation coefficient of length), s (standard error of mean length), t (Student-t value). For the computation of parameters the reader is referred to Imbrie (1956) and Marsal (1967). SYSTEMATIC DESCRIPTION Carbonita humilis (Jones and Kirkby, 1879) Pl. 1, figs. la-f; Pl. 2, figs. 3-9 1879. Carbonia fabulina var. humilis Jones and Kirkby, Ann. Mag. Nat. His¢t., ser. 5, vol. 4, p. 31, pl. 2, fig. 14. 1879. Carbonia fabulina var. inflata Jones and Kirkby, zdem., p. 31, pl. 2, figs. 15-19. 1884. Carbonia fabulina Jones and Kirkby, Geol. Mag., ser. 3, vol. 1, p. 358, pl. 12, figs. 9a-d. 1889. Carbonia fabulina var. altilis Jones and Kirkby, Geol. Mag., ser. 3, vol. 6, p. 270, text-fig. 114. 1930. Cytherella foveolata Wright, Proc. Manchester Lit. Phil. Soc., Mem., vol. 74, p. 49. pl. 1, figs. 2=2b. 1955. Whipplella cenisa Kremp and Grebe, Geol. Jb., vol. 71, pp. 152-155, pl. 16, figs. 3, 4. 1955. Whipplella rhenana Kremp and Grebe, idem., pp. 155-157, pl. 16, figs. 5meGe CARBONITA HUMILIS (JONES AND KiRKBY) 111 1957. Carbonita altilis Copeland, Geol. Sury. Canada, Mem., 286, p. 25, pl. 1, figs. 1-3, 15-18. 1957. Carbonita inflata Copeland, idem., p. 26, pl. 1, figs. 12-14, pl. 2, figs. 18, 19. 1966. Carbonita humilis Pollard, Palaeontology, vol. 9, pp. 683-685, text-fig. 6. 1967. Whipplella cenisa Bless, Freiberger Forschungschefte, C213, p. 162. 1967. Whipplella rhenana Bless, idem., p. 162, pl. 1, figs. 10, 10a, pl. 2, figs. 10, 13. 1970. Carbonita humilis Anderson, Geol. Sur. Great Britain, Bull. 32, pp. 87-90, Plea Steticse52-Si/empl. 19) igo. 1970. Carbonita inflata Vangerow, Palaeontographica, Abt. A, vol. 134, pp. 47, 48, pl. 13, figs. 14-20. 1972. Carbonita humilis Bless and Pollard, Meded. Rijks Geol. Dienst., N.S. 24, pp. 17-21, enclosures 2, 3, pl. 3, figs. 6-9, pl. 4, figs. 1-10, pl. 5, figs. 1-6, preprint available. Diagnosis. — Medium-sized, subovate Carbonita with rounded ends, gently arched to flattened dorsum, venter straight to convex, cardinal angles may be distinct, prominent dorsal groove between the valves, surface punctate. Distinct muscle-scar and vertical furrows on both sides of the muscle-scar, the posterior one being more prominent. Remarks.— As stated by Bless and Pollard in press, there exists con- siderable confusion in the literature about the distinction of species within the genus Carbonita, and even the genus is often poorly defined. This has re- sulted in an avalanche of names at the generic level and specific level. We believe, that C. humilis is distinguished from typical C. fabulina by the more subtriangular lateral outline of the latter. However, extreme variants of these species may be confused. We suppose C. humilis to be a direct descendant from C. fabulina. C. inflata is less easily distinguished from variants of C. humilis. Unfortunately, this is a rare form, and statistical methods for the separation of C. inflata as a species in its own right cannot be used up to now. Anderson (1970) apparently confused C. altilis with “Gutschickia’ bretonensis Copeland. Typical C. altilis as described and figured by Jones and Kirkby (1889) and by Copeland (1957), is very similar to typical C. humilis. There- fore, C. altilis is here included in C. humilis. American non-marine ostracodes from the Pennsylvanian, referred to as e.g. Cypridopsis fabulina (Scott and Summerson, 1943), Whipplella carbonaria (Scott, 1944), Carbonita magma, C. inflata, Gutschickia ovata (all described by Cooper, 1946) are most prob- ably conspecific with C. humilis. We refer to them as “C. humilis group”. VARIATION AND DIMORPHISM Already in 1879 Jones and Kirkby (pl. 2, figs. 11-14) showed the variation in shape of C. humilis, figuring specimens with different positions of maximum height. Kremp and Grebe (1955) distinguished between Whip- plella cenisa and W. rhenana (both considered here to be conspecific with General, C. humilis) because of differences in the relative position of maximum width and different H/L-ratios. Pollard (1966) was the first to postulate that these differences noted by Kremp and Grebe should be related to dimorphism. He stated that the supposed males were elongate-ovate in lateral outline, H/L 112 M. J. M. Biess anp J. E. PoLtarp ratio about .60, and had maximum height and width median, whilst the sup- posed females were subovate in lateral view, H/L ratio about .70, and had greatest height and width posterior of the middle. Unfortunately, his qualitative description was not supported by quantitative data. Examination of specimens from several horizons and locations of the West- phalian in NW Europe showed that the characters used by Pollard (1966) for the distinction of dimorphs may vary independently. In other words, dimorphs cannot be distinguished unless only one constant parameter is used. This ob- servation renewed discussion about the value of such a parameter for the distinction of dimorphs. Moreover, a recent study on a living parthenogenetic fresh-water ostracode by Szczechura (1971) showed that the parameters used by Pollard for the distinction of dimorphs may vary because of seasonal in- fluences. She noted variability in relative position of maximum width and height, absolute size of adults and shape. She pointed out that the differences noted might well have been explained as dimorphism, if it were not known from her observations that only female specimens were present. Thus, the para- meters in Pollard’s paper are not necessarily related to dimorphism. K. G. McKenzie (personal communication) states that size-ranges in recent dimorphic freshwater ostracodes which he studied, do not or only slightly overlap, if the specimens are collected alive. But when dealing with fossils size overlaps are common because several generations may be preserved in the same layer of sediment. He suggests, therefore, that “for fossils, shape characteristics must be used, and, usually, these are easy to determine for individual species with a little experience”. The unreliability of size as specific for dimorphic character in fossil ostracodes has also been pointed out by several other ostracode workers. Summarizing the above experiences and opinions we find that the recog- nition of sexual dimorphism in fossil podocopids is a problem, because dif- ferences in shape, size and form-ratios may occur in parthenogenetic as well as in syngamic species. Especially the distinction of dimorphs by only one character seems questionable. Therefore, we have tried to determine the possible relationship between characters useful for this purpose. First of all, we selected two relatively well-preserved assemblages of C. humilis, one from the G. B. 25 Band (Upper Westphalian A) of the Netherlands, and the other from the foveolata Band (Lower Westphalian C) of England. For a detailed description of these assemblages the reader is referred to Bless and Pollard (1972). One hundred and thirty-five specimens from the G. B. 25 Band, and 71 from the foveolata Band were then measured, and camera lucida drawings (scale 50:1) of left lateral and dorsal views made. The measurements included length, height and width. Also the relative position of maximum width and height, and the relative arching of the dorsum were determined. All these characters are variable and described below for the G. B. 25 Band. In specimens from the fovelata Band the arching of the dorsum and the relative position of maximum height appeared to be constant. Therefore, no further study was made of these two characters for the foveolata Band material. CARBONITA HUMILIS (JONES AND KIRKBY) 113 G. B. 25 Band.— The relationships between relative position of maximum height, relative position of maximum width, relative arching of the dorsum (as a function of variation of the lateral shape) and H/L-ratio for specimens from G. B. 25 Band is shown in a pictograph (Text-fig. 1b). The pictograph is explained in fig. 1a. One can immediately conclude that the relative position of maximum height is not related to dimorphism but is best considered to be related to the individual. B Hy ratio “I 0.56 ae dorsum|rounded (0) greatest |height 6s oe” 3 about| at < OR midlength ow py &, Q eR O> Ry << 2% KK@) re) oe & ee? OK” ro) o Berean broadly arched to straight se, / height about at midlength 3%, Y “ oS Sn, Ox / < Ay Oo 70 “Oxe oe @ Ce Ss SS, -D as ©e ey < dorsum a artenedl x oe LS mae cs OLS 65 % She - 9x TIS greatest| height 4 x Oe’ about! at = iS ® midlength O50 O45 ie Hy) ratio Text-fig. la. Wariation diagram for Carbonita humilis from G. B. 25 Band; explanation of Text-fig. 1b. 114 M. J. M. Bess ano J. E. PoLiarp © | \O. o Maximum width median eMaximum width posterior Text-fig. 1b. Variation diagram of Carbonita humilis from G. B. 25 Band (Upper Westphalian A), The Netherlands, showing relationship between relative position of maximum width, relative position of maximum height, relative arching of dorsum and H/L-ratio. CARBONITA HUMILIs (JONES AND KIRKBY) 115 0.60 oe . ° ee eee ee ¢ KM eXe &X ‘ x o XsessXe X Sex oe eX x xxM oe = 0.50 0.40 Height in mm ———> 0.70 0.80 0.90 lenin Ih) ili ———————=— Text-fig. 2a. Height vs. length diagram for Carbonita humilis from G. B. 25 Band. specimens with rounded dorsum X specimens with straightened dorsum 0.60 0.50 0.40 WA! -ratio 0.40 0.50 0.60 0.70 0.80 De Gasio Text-fig. 2b. Diagram of ratios W/L’ vs. H/L for Carbonita humilis from G. B. 25 Band. specimens with rounded dorsum x specimens with straightened dorsum 116 M. J. M. Biess anv J. E. PoLtarp Table 1. Statistical data for Carbonita humilis G. B. 25 Band, Upper Westphalian A, The Netherlands measurements in mm dorsum straightened dorsum rounded t* N 44 91 i, 0.83 0.81 1.98 H 0.54 0.53 2.61 Ww 0.43 0.43 od V 0.095963 0.092299 H/L 0.65 0.66 -0.99 W/L 0.52 0.54 -2.34 OS 0.74-0.92 0.69-0.92 S 0.04 0.05 iu S 0.03 0.05 H \ 4.34 6.17 s 0.0060 0.0052 *Student-t (d.f. = 133) = 1.98 (95 percent confidence level) Student-t (d.f. = 133) = 2.61 (99 percent confidence level) The relative arching of the dorsum may appear a more promising charac- ter when surveying the pictograph. Variability of H/L-ratio is less for speci- mens with a more or less straightened dorsum than for those with a more rounded dorsum. (Compare variation Series SW and S§ with Series NW and N). In the latter group the percentage of specimens with maximum width posterior is much higher (66% against 36% in the first group). However, plotting of specimens with straightened dorsum against specimens with rounded dorsum in a height vs. length diagram or W/L vs. H/L-diagram (Text-figs. 2a, 2b) does not reveal a marked separation between these points. Univariate analysis of the measurements for these two groups (Table [) reveals that there is no significant difference between the H/L-ratios, nor between the heights. There is a more significant difference (significant at the 5 per cent level) between the length and W/L-ratios for these groups. Only the difference between the heights is significant at the 1 per cent level. Because the relative arching of the dorsum remains constant (dorsum broadly arched) in the other assemblage from the foveolata Band, we feel that this character can hardly be used for the distinction of dimorphs. The relative position of maximum width has been determined in terms of maximum width median and maximum width posterior. In the very few cases, where the maximum width was anterior this has been put in our computations as being median. The pictograph shows that specimens with CARBONITA HUMILIS (JONES AND KIRKBY) 117 maximum width median have a different H/L-ratio range than those with maximum width posterior. This is easily shown in a frequency polygon (Text-fig. 3, lower part), but also in a height vs. length and W/L-vs. H/L- ratio diagrams (figs. 4a and b). Univariate analysis of the measurements (Table II) indicates that the differences between the height, width, H/L- and W/L-ratios for these two groups are significant at the 1 per cent level. Only the difference for the length is not significant. The relative position of maxi- mum width appears to be, therefore, a reliable character for the distinction of dimorphs in the G. B. 25 Band assemblage. No pictograph has been made for the foveolata Band assemblage, be- cause only two characters (relative position of maximum width and H/L- ratio) have been studied. As already explained above, the other characters are not believed to have any value for the distinction of dimorphs. 30 specimens 30 specimens 20 / \ 20 we \ 10 Ont f N Foveolata Band es Westphalian C Zs ° ° 40 30 20 10 / ° G.B.25 Band aig ff << Westphalian A Pi . 046 051 056 061 066 0.71 050 055 060 065 070 O77 Pireatio erate postition of maximum widlh median ---- position of mextrum walk postertor Text-fig. 3 Frequency polygon, showing relationship between position of maximum width and H/L and W/L’-ratios for Carbonita humilis. maximum width median ee ne maximum width posterior 118 M. J. M. Biess anp J. E. PoLtarp 0.70 0.80 0.90 Length) in am Text-fig. 4a. Height vs. length diagram for Carbonita humilis from G. B. 25 Band. specimens with maximum width median x specimens with maximum width posterior 0.60 0.40 0.50 0.60 0.70 0.80 afi - ratio Text-fig. 4b. Diagram of ratios W/L’ vs. H/L for Carbonita humilis from G. B. 25 Band. specimens with maximum width median x specimens with maximum width posterior CARBONITA HUMILIS (JONES AND KIRKBY) 119 Table 2. Statistical data for Carbonita humilis G. B. 25 Band, Upper Westphalian A, The Netherlands measurements in mm greatest width median’ greatest width posterior t® N 56 79 L 0.82 0.81 1.14 H 0.50 0.55 “7:15 Ww 0.42 0.45 -8.89 Vv 0.086100 0.100238 H/L 0.62 0.68 -7.46 W/L 0.51 0.55 -8.09 OR 0.72-0.92 0.69-0.92 L S 0.05 0.05 it S 0.04 0.04 H Vv 6.07 6.17 s 0.0067 0.0056 *Student-t ( 1.98 (95 percent confidence level) ae, = 133) = Student-t (d.f. = ey = 2.61 (99 percent confidence level) Plotting of the H/L-ratios against relative position of maximum width in a frequency polygon (Text-fig. 3, upper part) does not show any significant separation, nor does the plotting of the W/L-ratio against the relative position of maximum width. Height vs. length and W/L-vs. H/L-ratio diagrams again do not show any separation for specimens with maximum width median and posterior (Text-figs. 5a, b). Univariate analysis of measurements (Table III) confirms this at least in part. No significant difference has been found for the H/L-ratios, and the differences between the heights, widths and W/L- ratios are only significant at the 5 per cent level. The only difference, signifi- cant at the 1 per cent level, is that between the length of these forms. It should be noted, that in the case of the G. B. 25 Band assemblage the only difference not significant was that between the lengths. The mean volume (% LxHxW) of the foveolata Band specimens is about twice the value of the specimens from G. B. 25 Band (Tables II, III). As ostracodes approximately double in size between instars this fact suggests that there was one more instar of this species present in the foveolata Band than at the lower horizon. The question arises, therefore, whether this extra instar is a function of time (stratigraphically speaking) or of environment? DISCUSSION AND CONCLUSIONS In the previous section we have seen that the relative position of maximum width may be related to size and size ratios in some assemblages (e.g. 120 M. J. M. Bess anv J. E. Pottarp 0.70 xe exe e @oe eoxxe o& xx e e e eoeox oe XX xx xx e x eee ex E 0.60 eu . £ eeeX Cc ee ii x ~ e = x o =-0:50 0.90 1.00 1.10 Length in mm ——_ Text-fig. 5a. Height vs. length diagram for Carbonita humilis from foveolata Band. . specimens with maximum width median xX specimens with maximum width posterior 0.60 0.50 WA - ratio 0.40 0.50 0.60 0.70 H Y - ratio Text-fig. 5b. Diagram of ratios W/L’ vs. H/L for Carbonita humilis from foveolata Band. specimens with maximum width median x specimens with maximum width posterior CARBONITA HUMILIS (JONES AND KIRKBY) 121 Table 3. Statistical data for Carbonita humilis from foveolata Band (Lower Westphalian C), England. measurements in mm greatest width median greatest width posterior t® N 35 36 i 1.02 1.00 5.26 H 0.62 0.63 «2.63 W 0.55 0.57 -2.25 Vv 0.173910 0.179550 H/L 0.62 0.63 “it W/L 0.55 0.57 215 OR 0.92-1.08 0.91-1.07 L S 0.04 0.04 .% S 0.04 0.04 H Vv 3.92 4.00 8 0.0068 0.0067 *Student-t (d.f. = 69) Student-t (d.f. = = 2.00 (95 percent confidence level) 69) = 2.65 (99 percent confidence level) Westphalian A, Limburg and Durham, England). It is important to discuss whether this character may be related to sexual dimorphism or just to environmental influences. The work on living fresh-water ostracodes referred to previously (Szezechura, 1791 and McKenzie, personal communication) implies that it can be very difficult to distinguish between domicilial dimorphism and _ par- thenogenetic shape variability in some fossil cyprid ostracodes. Other workers (e.g. Morkhoven 1962; Keen, 1972) believe that certain ostracodes apparently may be either syngamic or parthenogenetic depending on environment. Pokorny (1965, p. 477) postulated that the parthenogenetic mode of reproduction may have been advantageous in a stable environment; presumably the reverse would also be true. Both Bate and Swain (discussion of Evenson, in Neale 1969, pp. 493-494) record the appearance of sexual dimorphism in pre-adult instars, or at least at different sizes, in both living and fossil ostracode species. The palaeoecology of these assemblages (Bless and Pollard 1972) suggested that while the faunal associations and fluctuating environment of the G. B. 25 Band are very close to those of the contemporaneous Hopkins Band (Pollard 1966, 1969) the fowveolata Band was deposited in a more restricted stable environment and so lacks the faunal and lithological succes- sions of the other two Bands. These above considerations suggest that at the present state of our knowledge there must be at least three possible explanations of the apparent 122 M. J. M. Biess anv J. E. PoLitarp dimorphism we see in C. humilis depending on the mode of reproduction of the species and its ecology. 1) C. humilis syngamic. Westphalian A faunas show marked sexual] dimor- phism and wide variability in an earlier instar than the less variable and poorly dimorphic Westphalian C assemblage. 2) C. humilis parthenogenetic. In this condition we could explain the West- phalian A faunas as showing wide variability similar to Recent Cyprinotus incongruens (Szczechura 1971) and growth arrested at an earlier instar than the less variable foveolata Band fauna. Such a difference in variability could be related to the more unstable environment of Westphalian A faunas already indicated by palaeoecology. 3) C. humilis either syngamic or parthenogenetic depending on environment. This third possibility combines features of the other two. The G. B. 25 Band assemblage was a syngamic population living in an unstable possibly unfavour- able environment producing wide variability and early sexual maturity or dwarfing, while the foweolata Band assemblage was a parthenogenetic popu- lation which grew to large size in a stable and favourable environment. It is interesting to record that assemblages of C. “altilis” (similar to C. humilis) of Westphalian B age from Joggins, Nova Scotia, are similar in size and variability to the foveolata Band population. They have similar faunal associates, preserved in shell beds which lack faunal or lithological phases, suggesting stable environmental conditions (see Bless and Pollard, 1972, p. 9). Which of these three or other possibilities is the most likely one we prefer to leave open until further information is available on assemblages of C. humilis from other stratigraphic levels. REFERENCES Anderson, F. W. 1970. Carboniferous ostracoda — the genus Carbonita Strand. Geol. Sur. Great Britain, Bull. 32, pp. 69-121. Bless, M. J. M., and Pollard, J. E. 1972. Paleoecology and ostracode faunas of Westphalian ostracode bands from Limburg, The Netherlands and Lancashire, Great Britain. Meded. Rijks Geol. Dienst, N.S. 24, pp. 1-34, preprint available. Cooper, C. L. 1946. Pennsylvanian ostracodes of Illinois. Illinois Geol. Sur., Bull. 70, PD UA7s Copeland, M. J. 1957. The arthropod faunas of the Upper Carboniferous rocks of the Maritime Provinces. Geol. Sur. Canada, Mem. 286, pp. 1-110. Evenson, C. D. 1969. Designation of lectotypes of fresh-water species described by Dob- bin, 1941 (Ostracoda, Crustacea) (in Neale, 1969, pp. 491-494). Imbrie, J. 1956. Biometrical methods in the study of invertebrate fossils. Am. Mus. Nat. Hist., Bull. vol. 108, pp. 211-252. Jones, T. R., and Kirkby, J. W. 1879. Some Carboniferous species belonging to the genus Carbonia Jones. Ann. Mag. Nat. Hist., ser. 5, vol. 4, pp. 28-40. 1889. On some Ostracoda from the Mabou Coalfield, Inverness Co., Cape Breton (Nova Scotia). Geol. Mag., ser. 3, vol. 6, pp. 269-271. CARBONITA HUMILIS (JONES AND KIRKBY) 1 Keen, M. C. 1972. Sannoisian and some other Upper Palaeogene Ostracoda from north-west Europe. Palaeontology, vol. 15, pp. 267-325. Kremp, G., and Grebe, H. 1955. Beschreibung und stratigraphischer Wert einiger Ostracodenfor- men aus dem Ruhrkarbon. Geol. Jb., vol. 71, pp. 145-169. Marsal, D. ; 1967. Statistische Methoden fiir Erdwissenschaftler. Schweizer — bart’sche Verlagsbuchhandlung, Stuttgart, pp. 1-152. Morkhoven, F. P. C. M. Van 1962. Post-Palaeozoic Ostracoda. Their morphology, taxonomy and economic use. Elsevier, Amsterdam, vol. 1, 204 pp. Neale, J. W. 1969. Editor. Taxonomy, morphology and ecology of Recent Ostracoda. Olivier and Boyd, Edinburgh, 553 pp. Pokorny, V. 1965. Some palaeoecological problems in marine ostracode faunas dem- onstrated on the Upper Cretaceous ostracodes of Bohemia, Czecho- slovakia. Pubbl. Staz. zool. Napoli, vol. 33 (supl.), pp. 462-479. Pollard, J. E. 1966. A non-marine ostracode fauna from the Coal Measures of Durham and Northumberland. Palaeontology, vol. 9, pp. 667-697. 1969. Three ostracod mussel bands in Coal Measures (Westphalian) of Northumberland and Durham. Proc. Yorks., Geol. Soc., vol. 37, pp. 239-276. Scott, H. W. 1944. Permian and Pennsylvanian freshwater ostracodes. Jour. Paleont. vol. 18, p. 141-147. Scott, H. W., and Summerson, C. H. 1943. Non-marine ostracoda from the Lower Pennsylvania in the south- ern Appalachians and their bearing on inter-continental correla- tion. Am. Jour. Sci., vol. 241, pp. 653-671. Szczechura, J. 1971. Seasonal changes in a reared fresh-water species, Cyprinotus (Heterocypris) incongruens (Ostracoda), and their importance in the interpretation of variability in fossil ostracodes. Bull. Centre Rech. Pau, SNPA, 5 suppl., pp. 191-205. ’ Martin J. M. Bless, John E. Pollard, Geological Bureau, Department of Geology, Akerstraat 86-88, University of Manchester, Heerlen, Netherlands. Manchester, England. DISCUSSION Dr. R. L. Kaesler: I think finding different sets of characters to be important in different faunas is a very important idea to recognize. It weighs against the outmoded idea that some characters are important at specific taxonomic levels. Dr. Whatley: I was very interested in the possible dimorphism you have discussed and wonder whether you might consider this as being seasonal in origin. Dr. Wall and I have observed a number of marine and freshwater species which exhibit in the adult stage noticeable changes in size and or shape 124 M. J. M. Bess anp J. E. PoLLarp depending upon at which time of the year the adults reach maturity. For example if within the same species certain individuals winter as adults, others as instars and yet others as eggs, when spring temperatures become suf- ficiently elevated for development to begin again, the three, what are es- sentially distinct, races of the population, will each go through its appropriate life cycle without being caught up or catching up with each other. We believe this to be responsible for observable seasonal differences in shape and size in Cythere lutea perhaps Heterocythereis albomaculata and in certain freshwater cyprids which are as yet not identified. PLAGE I All photographs of Plates I and II have been made in cooperation with the Working Group on Scanning Electron Microscopy of the University of Amsterdam. Figure 1. Carbonita humilis. Specimen 5, MJMB-collections; G.B. 25 Band, Upper Westphalian A, Emma Colliery, The Netherlands. la: dorsal view (scale = 200 microns). 1b: oblique antero-dorsal view of left valve (scale = 100 microns). 1c: left side of shell (scale = 200 microns). 1d: detail of fig. 1c, showing smooth area reflecting position of muscle scar (scale = 100 microns). le: detail of punctation posterior of muscle-scar area; note “striate” arrange- ment of punctae (scale = 20 microns). 1f: detail of punctae in center of fig. le (scale = 10 microns). 2. “Cythere cluthae.” Marine Pleistocene; North Sea Borehole (71H2, B11, 1 meter below substratum. Detail of punctation. Note remarkable resemblance to punctation of Carbonita humilis. Photograph by kind permission of A. Du Saar (Haarlem). (Scale = 200 microns). CARBONITA HUMILIs (JONES AND KIRKBY) 125 126 M. J. M. Biess anv J. E. PoLLarp > PLATE II Figure 3. Carbonita humilis. Specimen 1, MJMB-collections; foveolata-Band, Lower Westphalian C, Farnworth, Lancashire, England. 3a: left side of shell (scale = 200 microns). 3b: detail of punctation; note honey-comblike structure of punctae with very small muri between them, the whole approaching a reticulate ornamentation (scale = 20 microns). . Carbonita humilis. Specimen B2, MJMB-collections; fovcolata-Band, Lower Westphalian C, Farnworth, Lancashire, England. Left side of elongate shell partly coated with glue or matrix; note overlap along ends and venter (scale = 250 microns). . Carbonita humilis. Specimen 2, MJMB-collections; foveolata-Band, Lower Westphalian C, Farnworth, Lancashire, England. Left side of shell (scale = 200 microns). . Carbenita humilis. Specimen 3, MJMB-collections; foveolata-Band, Lower Westphalian C, Farnworth, Lancashire, England. Dorsal view, no overlap around ends (scale = 200 microns). . Carbonita humilis. Specimen t31, MJMB-collections; G.B. 25 Band, Upper Westphalian A, Emma Colliery, The Netherlands. Left side of shell (scale = 200 microns). . Carbonita humilis. Specimen 6, MJMB-collections; G.B. 25 Band, Upper Westphalian A, Emma Colliery, The Netherlands. Left side of shell (scale = 200 microns). . Carbonita humilis. Specimen 4, MJMB-collections; G.B. 25 Band, Upper Westphalian A, Emma Colliery, The Netherlands. 9a: left side of partly abraded shell showing internal mold with muscle-scar and vertical furrow posterior of this (scale = 200 microns). 9b: detail of muscle-scar (scale = 50 microns). CARBONITA HUMILIS (JONES AND KIRKBY) 127 SPREAD OF OSTRACODES TO EXOTIC ENVIRONS ON TRANSPLANTED OYSTERS Louis S. KorNICKER Smithsonian Institution ABSTRACT Sarsiella zostericola Cushman, 1906, is a highly ornamented, easily recog- nized myodocopid ostracode which has been previously reported along the northeast, West Coast and Gulf Coast of the United States. In 1967 and 1968, the species was collected along the coast of Essex, England. Because the ostra- codes of England are well known, it is suggested that S. zostericola is a recent arrival. One species of polychaete worm and two gastropods in the same area, also considered by others to be recent arrivals, are believed to have intro- duced with oysters transplanted from the northeast coast of the United States. It is tentatively concluded that §. zostericola was introduced to England in like manner. It is also suggested that a population of the species living in San Fran- cisco Bay, California, may have been introduced with oysters transplanted from the East Coast. There is a strong possibility that other species of ostra- codes have been spread widely by oysters. Recognition of these species is necessary for correct ecological and zoogeographical interpretations. LA DISSEMINATION DES OSTROCODES A DES ENDROITS EXOTIQUES SUR DES UITRES TRANSPLANTES RESUME Sarsiella zostericola Cushman, 1906, est un ostracode myodocopide, haute- ment ornamenté et facile a4 reconnaitre, qui a été rapporté antérieurement au long des cOtes nordest, ouest, et celle du golfe des Etats-Unis. En 1967 et 1968, Yespéce fut receuillie au long de la céte d’Essex en Engleterre. Puisque les ostracodes de |’Engleterre sont bien connus, il est suggéré que S. zostericola n’y est arrivé que recemment. Une espéce de polychaete et deux gastropodes dans la méme région, aussi considérés par d’autres comme des nouveaux venus, sont sensés avoir été introduits a travers des uitres transplantés des Etats-Unis. On arrive a la conclusion tentative que S. zosterico/a fut introduite en Engleterre dans une facon pareille. I] est aussi suggéré qu’unepopulation de |’espéce habi- tant dans la Baie de San Francisco en Californie, aurait pu s’introduire a travers des uitres transplantés de la céte de l’est. I] existe une forte possi- bilité de ce que d’autresespéce d’ostracodes ont été amplement disséminées par des uitres. La reconnaissance de ces espéces est nécessaire pour des interpréta- tions écologiques et zoogéographique scorrectes. INTRODUCTION The ornate, easily recognized myodocopid ostracode, Sarsiella zostericola Cushman, 1906, (Text-fig. 1) was described originally from shallow waters of Vineyard Sound, Massachusetts. Blake (1933) extended the known range of the species north to the Mount Desert Island region on the coast of Maine. I am able to extend the range south to the mouth of Chesapeake Bay, based on a specimen received from Dr. Joseph Hazel, collected aboard the R/V Gosnold in 1964 (Station 2051, 5 August 1964, 37°00.0’N, 75°15.0’W, 36 m, USNM 135400). Mr. Les Watling has informed me (in litt., 1972) that the species is also present in the coastal bays of Delaware (Cape Henlopen at the mouth of Delaware Bay; through Rehoboth Bay, and in the more saline regions of Indian River Bay). Its known range along the northeast Atlantic coast then, 130 L. S. KornicKER is from Chesapeake Bay to Maine. The species was not among the several myo- docopids found by Darby (1965) in the vicinity of Sapelo Island, Georgia. The distribution of S. zostericola is shown in Text-figure 2. Kornicker and Wise (1962) identified the species in collections from coastal lagoons of Texas. The occurrence of disjunct populations of S. zostericola along the eastern Atlantic coast and the southwestern Gulf Coast suggests that the species in the past lived also along the southeastern Atlantic and the northern and eastern Gulf coasts, possibly during colder climates of the Pleistocene. Jones (1958a, 1958b) reported S. zostericola (= S. tricostata Jones, 1958) from San Francisco Bay, California. I compared in detail specimens of the species from Massachusetts, Texas, and California, and could find no dif- ferences (Kornicker, 1967). I propose here that the population in San Fran- cisco Bay was transported along with oysters which were transplanted from the East Coast during the years 1870 to 1910. Text-figure 1. Lateral view of left valve of Sarsiella zostericola (USNM 139287) from station 139, River Blackwater, Essex, England, length 1.39 mm (stereographic pair). ACKNOWLEDGMENTS I thank Dr. Eric Robinson for sending specimens of §. zostericola from England, Dr. Joseph Hazel for a specimen of S. zostericola from the mouth of the Chesapeake Bay, and Mr. Les Watling for information concerning distribution of the species along the Delaware coast. I thank also the following individuals for information concerning oysters: Dr. Austin B. Williams, Dr. James E. Hanks, Dr. A. F. Chestnut, and Mr. J. Richards Nelson. Dr. M. Pettibone, in addition to criticizing the manuscript, supplied valuable informa- tion concerning the introduction of polychaetes to English waters. I thank also Dr. T. E. Bowman, Dr. I. G. Sohn, and Dr. J. E. Hazel for criticizing the manuscript. The SEM photograph of the ostracode valve was made by Mr. Walter Brown. 13st OsTRACODE SPREAD ON OYSTERS °2109149480% *§ JO UOIINGIIjsIp Surmoys dey *Z a1nB1j-}xa9 J, S3ivis QgQ3aliINnn 132 L. S. KorNICKER TRANSPORTATION BY OYSTERS The oyster Crassostrea virginica (Gmelin) endemic to the Atlantic and Gulf Coast of the United States, was first transplanted from the East Coast to San Francisco Bay in 1869 or 1870, but it was not until 1875 that seed-oysters were imported in large quantities. About 9000 barrels of seed-oysters were transplanted each year from the East Coast until 1910 when the project was discontinued (Smith, 1896; Barrett, 1963). The source of the East Coast seed- oysters was in the vicinity of Chesapeake Bay, Connecticut, and New York. The oyster drill, Urosalpinx cinerea (Say) and the American slipper-shell, Crepidula fornicata Linné, both endemic to the Atlantic Coast, were introduced to the West Coast with the transplanted oysters (Walne, 1956; Elton, 1958; Galtsoff, 1964). Therefore, it is not unreasonable to suppose that S. zostericola was introduced the same way. Unfortunately, the absence of collections of ostracodes from San Francisco Bay prior to 1870 makes it impossible to give historical support to the hypothesis. The living ostracodes of England have received considerable study and are better known than in most other areas (Neale, 1965). Although species of the genus Sarsiclla have been reported from the well-studied coasts of the British Isles, S. zostericola was not among them. Thus, it is reasonably safe to assume that numerous specimens of S. zostericola collected in 1967-1968 along the shore of Blackwater estuary in Essex, are part of a population that only recently arrived in England. The ostracodes (USNM 139287) were sent to me by the collector, Dr. Eric Robinson. The history of some additional organisms, including two species of gastropods and a polychaete worm, makes it possible to postulate with some confidence that the ostracodes were introduced with oysters that had been shipped from the eastern coast of the U.S.A. and reset in estuaries along the coast of Essex (Text-fig. 3). The oyster, C. virginica, does not establish breeding populations in the waters of England, but from about the late 1870’s to 1940, young oysters and seed-oysters were transported from the East Coast of the U.S.A. (Chesapeake Bay, Conn., N.Y.) to England, where they were relaid in suitable coastal estuaries unti] ready for harvesting (Cole, 1956b; Philpots, 1891b). One such locality was in the River Colne, near Brightlingsea, Essex. Some of the oysters from that area were transferred to other localities in Essex, including River Blackwater, River Crouch, and River Rouch. An estuary near Whitstable, Kent, was another locality where American oysters were transplanted either directly from America or from the River Colne. These localities were important eco- nomically because of their proximity to the London Market. The ostracodes of the Thames estuary were studied by Brady and Robertson (1870). The American slipper-shell, Crepidula fornicata, was transported on eastern oysters to England, probably in the 1880’s (Loosanoff, 1955), but it was col- lected first in the River Crouch in 1893 (Crouch, 1895; Robson, 1929; Mc- Millan, 1939; Cole, 1952, 1956a) and then in the River Colne near Brightlingsea OsTRACODE SPREAD ON OYSTERS 133 ESoe x RIVER COLNE Sarsiella ee —— zostericola = RIVER BLACKWATER 1967), 1 irosuipinx F — F cinerea <= Sarsiella pecker oso = zostericola : p= a AMERICAN Brepiduiag 268) eri guanine) RPSOYSTERS fornicata RIVER’E& =s—— ROACH er ee SE Ere | RIVER THAMES . . . Clymenelia ISLE OF SHEPPEYA *. torquata Text-figure 3. Map of southeast coast of England (Essex and Kent) show- ing areas where oysters, Crassostrea virginica, from the United States have been reset and the localities and dates of the initial appearance of other species introduced with the oysters. 134 L. S. KornicKER in 1898 (Crouch, 1898; Mistakidis, 1951). The slipper-shell spread rapidly after 1920 along the south coast of England (Cole, 1956b) and subsequently ex- tended its range into the coastal waters of western Europe (Loosanoff, 1955). The American oyster drill, Urosalpinx cinerea, was first collected in Europe in 1920 in the oyster beds of the River Blackwater (Orton, 1930) (Text- fig. 3). By 1942 it was abundant in the River Blackwater and other creeks and rivers along the Essex coast, as well as at the mouth of the estuary near Whitstable in Kent. All these areas were used for culturing American oysters, and it has been assumed by all investigators that the drill] was carried to these areas on transplanted oysters (Orton, 1927, 1930; Orton and Winckworth, 1928; Robson, 1929; Orton and Lewis, 1931; Cole, 1942, 1956a; Hancock, 1954; Newell, 1954). More recently a polychaete worm, Clymenella torquata (Leidy), was dis- covered in the intertidal area of Whitstable by Newell (1949a, 1949b) (Text- fig. 3). He believed that the worms might have been introduced in 1936 when American oysters were introduced at Whitstable. The known range of C. torqguata along the North American coast is from the Gulf of St. Lawrence to Florida, and on the Louisiana Coast of the Gulf of Mexico (M. Pettibone, written comm. 1972). The proposition that §. zostericola was transported with oysters to Essex, England, is supported by both historical and circumstantial evidence. If ostra- codes can be transported from the East Coast of the U.S.A. to England in this manner, it should also be possible for them to be transported from the east to west coasts of the U.S.A. Thus, the evidence from England lends support to the hypothesis that the population in San Francisco Bay was also derived from the East Coast. The known localities at which the species lives indicate that its climatic range is warm temperate to Boreal (Hedgpeth 1957). It may be safe to assume that other ostracode species also have been transported elsewhere with oysters. According to Elton (1958, p. 100), the business of oyster culture must be the greatest of all agencies for spreading marine animals to new quarters of the world. Few areas seem to have been missed being at least tested for their potential for culturing foreign oysters. A major current operation, starting in 1902, is the transport of seed-oysters of Crassostrea gigas (Thunberg) from Japan to the west coast of the U.S.A. and Canada. As a result of this, an oyster drill, Tritonalia japonica Dunker, a Japanese clam, Paphia philippinarum (Adams and Reeve), and a parasitic copepod, Mytilicola orientalis Mori, have been introduced to the west coast of the U.S.A. and Canada (Elsey, 1934; Wilson, 1938; Odlaug, 1946; Kincaid, 1953; Galtsoff, 1964). Smaller numbers of seed-oysters have been transported from Japan to Hawaii (Edmundson and Wilson, 1940), Australia (Thomson, 1952), China and far-east islands (Cahn, 1950). The European oyster, Ostrea edulis Linné, was transplanted from Holland to Connecticut and Maine in 1949; young oysters from the resulting New England beds were later trans- planted to the coast of Washington (Loosanoff, 1955). Considerable transplanta- tion of oysters has taken place since early times among the countries of Europe, OsTRACODE SPREAD ON OYSTERS 135 e.g., from Portugal and France to Britain, from England and France to Italy, from Scotland and Ireland to England (Philpots, 1891a, 1891b). Along the northeast coast of the U.S.A., seed-oysters from the Chesapeake Bay area have been used to supply nurseries in Connecticut, New York, and Rhode Island; seed-oysters from the Connecticut nursery later formed the basis for oyster beds in Massachusettes (Philpots, 1891b). In answer to a letter requesting information concerning current practices in the transplanting of oysters, I received from Mr. J. Richards Nelson, Presi- dent, Long Island Oyster Farms, Inc., New Haven, Connecticut, a letter (Feb. 1972) containing the following excerpt, “. . . oysters have been transplanted from Gardiners Bay, Long Island [New York] to Tomales Bay, California, for at least the past forty years to my knowledge, and probably longer. Prior to 1940 they were sent by freight car, and it required thirteen days between the time they were taken from Gardiner Bay beds to the time of planting in California. Since that time the transportation has been by refrigerated trailer trucks and the trip is accomplished in five days. The J. & J. W. Elsworth Co. of Greenport, New York, furnished most of these oysters until 1968, when Long Island Oyster Farms bought the Elsworth Co. assets. It is my understanding that there have been some oysters transplanted from Delaware Bay and Chesa- peake Bay to Tomales Bay, but I understand that the northern oysters from Gardiners Bay are preferred. The Gardiner Bay oysters all come from Con- necticut in the vicinity of New Haven or Bridgeport and are generally trans- planted at the age of two years, remaining on the Gardiner Bay beds from one to two years, the stock going to California being at least three years old and generally four. Gardiners Bay does not produce any natural set and all stock there is transplanted from Connecticut.” In an interesting paper entitled, “The shell of Ostrea edulis as a habitat’, Korringa (1954, p. 113) reported the following podocopid ostracodes occurring on oysters shells in beds of the Netherlands: Loxoconcha impressa (Baird), Leptocythere castanea Sars, Heterocythereis albomaculata (Baird), Hirschman- nia viridis (O. F. Miller), Cytherura nigrescens (Baird), Cytherois fischeri Sars, Hemicythere villosa (Sars). Swain (1955) and King and Kornicker (1970) listed podocopid ostracodes associated with oyster “reefs” in bays along the coast of Texas. CONCLUSIONS In summary, I have presented evidence supporting the hypothesis that 8S. zostericola was introduced to San Francisco Bay, California, and to the River Blackwater, England, with oysters from the east coast of the United States. Thus, there is a strong possibility that ostracodes have been introduced with transplanted oysters in, or near, areas where oysters are being, or have been, cultured. Therefore, this factor should be taken into account in investigations dealing with estuarine and coastal ostracodes. 136 L. S. KornicKer LITERATURE CITED Barrett, E. M. 1963. The California oyster industry. Resources Agency California, De- partment Fish and Game, Fish Bull., 123, 103 pages. Blake, Charles 1933. Ostracoda. In Biological Survey of the Mount Desert Region con- ducted by William Procter, V, pp. 229-241, figs. 39, 40. Brady, G. S., and Robertson, D. 1870. The Ostracoda and Foraminifera of tidal rivers. Ann. Mag. Nat. Hist., Ser. 4, 6, pp. 1-33, plates 1-10. Cahn, A. R. 1950. Oyster Culture in Japan. United States Depart. Interior, Fish and Wildlife Ser., Fishery Leaflet, 383, 80 pages. Cole, H. A. 1942. The American whelk tingle Urosalpinx cinerea (Say), on British oyster beds. Jour. Marine Biol. Assoc. United Kingdom, XXV (3), pp. 477-508. 1952. The American slipper limpet (Crepidula fornicata L.) on Cornish oyster beds. Fisheries Invest., London, Ser. 2, 17 (7), pp. 1-13. 1956a. Benthos and the shellfish of commerce. In Sea Fisheries: Their Investigation in the United Kingdom (Ed. M. Graham) London, pp. 139-206. 1956b. Oyster cultivation in Britain. A Manual of Current Practice, Lon- don, 43 pages. Crouch, W. 1895. On the Occurrence of Crepidula fornicata in Essex. Proc. Malacol. Soc., London, 1, p. 19. 1898. Further notes on the occurrence of Crepidula fornicata L., in Essex Waters. Essex Natu., 10, p. 353. Cushman, J. A. 1906. Marine Ostracoda of Vineyard Sound and adjacent waters. Bos- ton Soc. Nat. Hist., Proc., 32 (10), pp. 359-385, pls. 27-38. Darby, D. G. 1965. Ecology and taxonomy of Ostracoda in the vicinity of Sapelo Is- land, Georgia. Report No. 2 in Four Reports of Ostracod Investi- gations (offset report is issued by the University of Michigan), ili-vi + 1-76, text-figures 1-89. Edmundson, C. H., and Wilson, I. H. 1940. The shellfish resources of Hawati. Sixth Pacific Science Congress of the Pacific Science Association, Proc. III, pp. 241-243. Elsey, C. R. 1934. The Japanese oyster in Canadian Pacific waters. Fifth Pacific Science Congress, Canada, 1933, Proc., pp. 4121-4127. Elton, C. S. 1958. The ecology of invasion by animals and plants. Methuen & Co. Ltd., London; John Wiley & Sons Inc., New York, 181 pp. Galtsoff, P. S. 1964. The American oyster Crassostrea virginica Gmelin. United States Depart. Interior, Fish and Wildlife Service, Fishery Bull., 64, 480 pages. Hancock, D. A. 1954. The destruction of oyster spat by Urosalpinx cinerea (Say) on the Essex oyster beds. Journal du Conseil, Conseil Permanent pour L’Exploration de la Mer, XX (2), pp. 186-196. OsTRACODE SPREAD ON OYSTERS 137 Hedgpeth, J. W. 1957. Marine biogeography. Pages 359-382, In Treatise on Marine Ecology and Paleoecology, vol. 1, Ecology. The Geol. Soc. America, Mem. 67, 1296 pages. Jones, M. E. 1958a.Sarsiella tricostata, a new ostracod from San Francisco Bay (Myodocopa: Cypridinidae). Jour. Washington Acad. Sci., 48 (2) pp. 48-52, figures 1, 2. 1958b. Further notes on Sarsiella tricostata. Jour. Washington Acad. Sci., 48 (7), p. 238, figs. 1-3. Kincaid, T. 1953. The acclimatization of the Pacific oyster (Ostrea laperousti = Ostrea gigas Thunberg) upon the West Coast of North America, Seventh Pacific Science Congress of the Pacific Sci. Assoc. Zoology, Proc. IV, pp. 508-512. King, C. E., and Kornicker, L. S. 1970. Ostracoda in Texas bays and lagoons. An Ecologic Study. Smith- sonian Contrib. Zoology, 24, 92 pages, figs. 1-15, pls. 1-21. Kornicker, L. S. 1967. A study of three species of Sarsiella (Ostracoda: Myodocopa). United States Nat. Mus., Proc., 122 (3594), 46 pp., figs. 1-19, pls. 1-4. Kornicker, L. S., and Wise, C. D. 1962. Sarsiella (Ostracoda) in Texas bays and lagoons, Crustaceana, 4 (1), pp. 57-74, fig. 1-10. Korringa, P. 1954. The shell of Ostrea edulis as a habitat. Archives Néerlandaises de Zoologie, KX, pp. 32-152, figs. 1-13. Loosanoff, V. L. 1955. The European oyster in American waters. Science, 121 (3135), pp. 110-121. McMillan, N. F. 1939. Early records of Crepidula in English waters. Malacol. Soc. Lon- don, Proc. XXIII, p. 236. Mistakidis, M. N. 1951. Quantitative studies of the bottom fauna of essex oyster grounds. Ministry Agriculture Fisheries, Fisheries Invest., London, ser. II, XVII (6), 47 pages. Neale, J. W. 1965. Some factors influencing the distribution of Recent British Ostra- coda. Pubblicazioni Della Stazione Zoologica Di Napoli, 33 suppl., pp. 247-307, figs. 1-11, plate 1. Newell, G. E. 1949a. The occurrence of a species of Clymenella Verrill (Polychaeta, fam. Maldanidac) on the North Coast of Kent. Nature, CLXIII (5), pp. 111-115. 1949b. Clymenella torquata (Leidy), a polychaete new to Britain. The Ann. Mag. Nat. Hist., ser. 12, II (VI), pp. 147-155. 1954. The marine fauna of Whitstable. Ann. Mag. Nat. Hist., ser. 12, 7 (77), pp. 321-250. Odlaug, T. O. 1946. The effect of the copepod, Mytilicola orientalis upon the Olympia oyster, Ostrea lurida. American Micro. Soc., Trans., LXV (4), pp. 311-317. 138 L. S. KornicKER Orton, J. H. ’ 1927. The habits and economic importance of the rough welk tingle (Murex ecrinaceus). Nature, 122 (3027), pp. 653-655. 1930. On the oyster-drills in the Essex estuaries. Essex Naturalist, XXII (VI), pp. 298-306. Orton, J. H., and Lewis, H. M. 1931. On the effect of the severe winter of 1928-1929 on the oyster drills of the Blackwater Estuary. Jour. Marine Biol. Assoc. United King- dom XVII, pp. 301-313. Orton, J. H., and Winckworth, R. 1928. The occurrence of the American oyster pest Urosalpinx cinerea (Say) on English oyster beds. Nature, CXXII, p. 241. Philpots, J. R. 1891a. Oysters, and all about them. John Richardson and Co., London, J, 642 pages. 1891b. Oysters, and all about them. John Richardson and Co., London, II, pp. 643-1370. Robson, G. C. 1929. On the Dispersal of the American Slipper Limpet in English Waters. Malacol. Soc. London, Proc. XVIII, p. 273. Smith, H. M. 1896. A review of the history and results of the attempts to acclimatize fish and other water animals in the Pacific States. United States Fish Commission, Bull. 1895, 15, pp. 379-472. Swain, F. M. 1955. Ostracoda of San Antonio Bay, Texas. Jour. Paleont., 29 (4), pp. 561-646, figs. 1-39, pls. 61-64. Thomson, J. M. 1952. The acclimatization and growth of the Pacific Oyster (Gryphaea gigas) in Australia. Australian Jour. Marine Freshwater Research, 3° (1), pp. 64-73: Walne, P. R. 1956. The biology and distribution of the Slipper Limpet Crepidula fornicata in Essex rivers with notes on the distribution of the larger epi-benthic invertebrates. Fisheries Investigations, London, ser. 2, 20 (6), pp. 1-50. Wilson, C. B. 1938. A new copepod from Japanese oysters transplanted to the Pacific Coast of the United States. Washington Acad. Sci. Jour., 28 (6), pp. 284-288. Louis S. Kornicker National Museum of Natural History Smithsonian Institution Washington, D.C. 20560 DISCUSSION Dr. R. C. Whatley: How are the ostracodes transported ? Dr. Kornicker: In between the oysters and in any sediment that might go along with the oysters. Dr. P. A. Sandberg: How do the Japanese prepare the oysters for shipment? Dr. Kornicker: Because of questions following my paper concerning details of shipping oyster spat from Japan, I think it best to replace my incomplete answers with the following quote from Barrett (1963, p. 50). OsTRACODE SPREAD ON OYSTERS 139 “Raising and packing seed oysters for export requires special care to enable the seed to survive the trans-Pacific voyage, and to ensure that it will be free of harmful organisms. Oyster spat is caught on empty shells of oysters and other mollusks, which are strung on wires and suspended from rafts or racks in areas where spat-setting is known to occur (Figure 8). The strings of shells are put into the water in July when the young oysters are ready to set, keeping them above the bottom, which is habitat of harmful oyster drills. The spat that set on the shells are left unti] about September, at which time the strings are removed from the floats and racks and piled horizontally on low racks in the intertidal zone where the spat are exposed to the air for several hours each day during ebb tides (Figure 9). This exposure causes the young oysters, which at this stage are less than 1/2-inch in diameter, to de- velop thick, strong shells that do not allow water to escape, thus enabling them to survive during the periods of exposure to the air. Spat not exposed to these conditions develop larger meats and thinner shells which are not water-tight and whose edges chip easily. The spat to be exported are left on the “harden- ing” racks until about January or February when packing for shipment begins. “The spat containing shells are removed from the wire strings, washed, sorted, inspected and packed in wooden cases. Much of this work is done in the open air by women at many small sites in the growing areas (Figures 10, 11, 12). Women who do the sorting remove drills and drill egg cases, count the number of live spat per shell to make sure there are the minimum number required, and sort broken and unbroken shells.” Dr. H. Loffler: If this is true, passive dispersion by birds may not be ex- cluded. I don’t know how many species have been checked for the possibility of internal transportation by birds. Dr. Kornicker: Well, we can speculate on quite a few ways ostracodes could be transported but I think in this case, being Sarsiella zostericola is found in an oyster area and with three other species that have been interpreted as having been carried in with oysters, species that could not have been transported by birds, transportation by oysters seems more likely. Mr. L. Watling: Oysters transported from the West coast to the East coast are generally hosed down but sometimes mud remains in the crevices. Another point I would like to make is that a species I found in California and described as Spinileberis hyalinus would appear, from specimens that Dr. Ishizaki sent me, were the same as §. guadriaculeata from Japan. I believe it was trans- ported since I found it near oyster beds in a small bay in California. These oysters (Crassostrea gigas) had come from Japan. Dr. Kornicker: That’s very interesting. alk wy ra ‘ : wo n " me y giitens me} iat Fi if ; ; 4 7 : ath 1a : j . a: iat aking ‘ as e a nM bt > Shea, 9 ‘s . i pss es saul a _ allt erga on le slay be =e “ah, wy tah pet hd cr te ithe aN ele malt he wdl” ntend ol} rev Ww | segett aj ky i hs ain sal, ah Rae a ete ‘ 7 oe gy it=¢ : ey fl ittede 490 a4 pre i Liiva. Se ite Kathe sine pe ‘ Gs Bul fii a 4 i” 9 yyi 1 i y> ad “1 ts We tal rf are . ‘ } ‘ 104 pati ene mapu tad iW te t ' i yee? bAy at @e allele a an 1) 7 qiale f->¢9 ) i ire ® 4» fnny a” hi rene a F . ‘ co. pus Wy hy 4 i -_ ) we Ms, ee 5 iow ro ewe Fete in ef nofqa : ow ie ost " . | ta) (seo i 1 lf py pn ‘ tw al hea sli oqenint $4) CANONICAL CORRELATION ANALYSIS OF HEMICYTHERINID AND TRACHYLEBERINID OSTRACODES IN THE NIGER DELTA R. A. REYMENT Paleontologiska Institutionen, Uppsala Universitet ABSTRACT The multivariate statistical method of canonical correlation was applied to observations made on the interstitial environment of ostracodes occurring in the Niger Delta. The regression structure provided by this method was made up of the predictor set (pH, Eh, depth of sample (D), and total contents of phosphorous and sulfur), and the response set (total content of organic sub- stance (OC), total content of calcium carbonate (CA), and total number of hemicytherinids and trachyleberinids (OSTR)). Only one of three canonical correlations proved significant; it is based almost entirely on a predictor set representing mainly § and a response set consisting of positive covariation in OC and OSTR. This canonical correlation indicates that much of the organic substance (divorced from shell) is correlated with S (probably derived from decomposing organic matter). The second, non-significant, canonical correla- tion indicates that the distribution of the shells (including ostracode shells) is determined by a predictor set dominated by D in negative covariation with P. The graphical analysis of the transformed data scores shows the ostracode- rich samples form a well defined cluster. RESUME La méthode de la statistique multivariée, nommée “la corrélation canonique” était appliquée a des données du milieu interstitiel de quelques groupes d’os- tracodes du delta nigérien. Cette méthode donne une structure de régression avec un ensemble de prédiction (ici pH, Eh, profondeur de |’échantillon, D, et les dosages de P et S) et un ensemble de résponse (ici les totalités de matiére organique, OC, CaCOs;, CA, et le nombre d’ostracodes des groupes des hemicy- therines et trachyleberines (OSTR). Une seule des racines de la corrélation canonique est significative; elle est basée, presque entiérement, sur un ensemble prédicteur composé uniquement de S, et un ensemble de réponse contenant les variables OC et OSTR dans une covariation positive. Cette relation montre qu’une grande partie de la matiére organique (dépourvue de fragments des parties dures) est correlée avec S provenant probablement de la décomposition de la matiére organique). La deuxiéme racine indique que la_ répartition des coquilles (y compris les carapaces des ostracodes) est déterminée par un ensemble prédicteur dont les variables dominantes, D et P, se trouvent en corrélation négative. INTRODUCTION M. E. Omatsola (1970) recently described the ostracodes of the Niger Delta in some detail. The samples from which his specimens were extracted were collected in a survey of the interstitial ecology of that delta (Reyment, 1969). These samples have been analyzed for a wide range of variables (pH, Eh, organic content of the sediment (OC), total calcium carbonate (CA), and various chemical constituents, including total phosphorus and total sulfur), and it was considered of interest to see whether the abundances of the ostracodes in the samples could be related to any of them. This report presents the results of a generalized regression approach to the problem. Interest is also attached to the isolation of redundant variables. The calculations were made on the CDC 3600 machine of the Computing Centre of the University of Uppsala and financed by Computing Grant 104104 of that university. 142 R. A. REYMENT THE VARIABLES The variables on which this study was based are: pH and Eh of the interstitial water of the sediment, the total organic content of the sediment, the total content of calcium carbonate (mainly derived from shells from all sources), distance of the sampling site from the shore, counts of ostracode frequencies of each sample, total phosphorus in the sediment, and sulfur from all sources. Although it had already been established in another investi- gation (Reyment, 1972) that pH and Eh contribute little to an analysis of the interstitial deltaic environment, they were included here for completeness (pH can hardly be expected to vary much owing to the buffering effect of sea- water). BIVARIATE CORRELATIONS It is instructive to consider the significant bivariate correlations before proceeding to the main analysis. These correlations are listed in Table 1. Most of these seem to make sense. Organic substance is a logical correlate of the soft parts of living ostracodes and the high value of 0.76 for its correla- tion with sulfur (also ostracodes) can reasonably be related to decomposing organic matter and associated §, and HS. The relatively high value for calcium carbonate and ostracodes, is also expected. The positive correlation between D and P is a well known characteristic of the sediments of shallow seas (cf. Degens, 1968). Table 1. Significant bivariate correlations Variables Tij Variables Tj pH - Eh 0.54 CA -OSTR 0.49 OC - OSTR 0.43 D-P 0.73 OC-S 0.76 D-S 0.49 THE CANONICAL CORRELATION ANALYSIS Inasmuch as the biological interpretation of canonical correlation studies has recently been discussed at length by Blackith and Reyment (1971) and Reyment (1972), I propose to pass directly to the interpretation of the present results and refer the reader who has not yet made contact with morphometric methods of analysis to the above sources. There is only one significant canonical correlation, namely, Re = 0.85, which is associated with a chisquare value of 29.2 for 15 degrees of freedom. The second canonical correlation is 0.47, which for 8 degrees of freedom, is associated with a chisquare of only 5.7. Most of the information, therefore, resides in the first correlation. The set of predictor variables for the first canonical correlation has the composition: (0.4D, -0.3P, 1.28); Al os. eue se) co yovetiene eee (C152 060107 18) ORNS ea RL AE ol oe seh Bc eliek? oes Sac) eee INCOM SMe (outs: telhsh sie) ie eyenere RESPONSES sl eebreten tenet Seek ia Be qe 8 LN OS ot a eee he ieee o Beer 05g OS ell Sk GARR > a eae) TO CeO ay shitbelte? oe) UAT Te Oy teebrs otek cree euyy 2! 1S PC HO) ROA WE ay oh) Mr, AS i ic ects ee aire tonne) Seems ct NT CURR gfe) ete os omeren (ge ae ep Ssuciie Yay aot SOS ew te ot Crees Sone . . SEE OR I Oy Seay ot amieniaeaer CH EC) Sie agape Wontar aioe FESO KS AN tess epepeesiia? Mapa heise Met rah “onk8) eee a2 Le Se, ei cian IY, A gre lan a SOME Wee mien | Pt eC Ane Gin aes ee, ©) Sie Ry eeafie tauren ets *nedl Sire. curren as Siey toi ouebion eres euli(yry cs 4 (lus od ee Ol Feisie elke. le Suid, te Lo, Sp © 10 Gl Text-fig. 1. Graph of the transformed variates of the first canonical correla- tion. The axes denote the predictor and response variables. The letter-number combinations denote sampling sites (cf. Reyment, 1969). 144 R. A. REYMENT here, pH and Eh are entirely without significance. The set of response variables corresponding is: (0.60C, -0.3CA, 0.60STR). The important correlations between the original variables and the canonical variates are, for the predictors: =0.20): 0:22 1:05; This result indicates that the content of total S predicts the occurrence of organic matter in the sediment, including the soft parts of ostracodes, when these are not associated with shell. The poor performance of CA in this relationship is certainly a consequence of the masking effect of the shell substance of molluscan origin. The response correlations are: 1.00C: 0.70STR. This pair of canonical variates may be taken to represent the relationship developing between decomposing organic substance and concentration of HS. A graph of the predictor and response canonical variates is shown in Text- fig. 1. All of the samples in the upper, dotted part of the graph are rich in ostracodes in relation to mollusks. The samples in the lower, left-hand part of the graph tend to be poor in ostracodes, or to lack them, but they are usually rich in molluscan shells and shell detritus. The graphical analysis brings out a second characteristic in the association between the two sets of variables, and is one of the major results of the analysis. The second, non-significant canonical correlation is of interest, despite the fact that it does not represent more than a small part of the interrelation- ships in the material. The set of predictor variables is dominated by the covariational vector (0.8D, -0.6P). The response vector is (0.9CA, 0.4O0STR). This relationship suggests that where distance from the delta shore is negatively correlated with P, shell accumulations tend to occur, including the shells of ostracodes. It is necessary to bear in mind that this tendency is only represented in a fraction of the material. REFERENCES Blackith, R. E., and Reyment, R. A. 1971. Multivariate Morphometrics. Academic Press, London, New York, IX, 412 pp. Degens, E. T. 1968. Geochemie der Sedimente. F. Enke Verl., Stuttgart, VIII, 282 pp. Omatsola, M. E. 1970. Studies on Recent Ostracoda (Crustacea, Arthropoda) from the Niger Delta, Nigeria. Ph.D. Thesis, University of Uppsala. Reyment, R. A. 1969. The interstitial ecology of the Niger Delta. Bull. geol. Instn. Univ. Upsala, NS 1, pp. 121-159. 1972. Models for the study of zinc and lead in a deltaic environment. Section 9b. 8th Internat. Sed. Congr. (Heidelberg, 1971). Plenum, New York. R. A. Reyment, Paleontologiska Institutionen, Uppsala Universitet, S-751 22 Uppsala, Sweden. CANONICAL CORRELATION OstTRACODEsS OF NIGER DELTA 145 DISCUSSION Dr. J. W. Neale: Did you measure current velocity and was there any cor- relation with sulfur content and hence with your ostracode environments? Dr. Reyment: That is, of course, a difficult question. The samples were taken in a delta of quite some size, the front of which is 300 miles, and while some work has been done by Longhurst (1964) on the currents in the delta, we have no exact measurements, nor the equipment to do such observations. Dr. Neale: Were pH, Eh, S measured at the time or was there an appreciable time gap between the measurement of these and the date of the samples? Dr. Reyment: The samples were taken by means of a Ziillig sampler; they were analyzed on board ship immediately after having been taken up. I wrote this up in 1969 in the paper on the ecology of Niger Delta. The Zillig sampler enables one to sample directly by sticking a coarse hypodermic needle straight into the sediment. Dr. J. E. Hazel: Did you do any other analyses other than ecological variations in order to see if you were getting similar results? Dr. Reyment: I used principle components and a canonical variational study. I have a paper in the Sedimentological Congress Proceedings (Reyment, 1972) on this same technique, applying it to the same material, but in relation to the occurrence of zinc and lead in the sediments. If you do the analysis the other way around, you get only the roots and vectors extraction. You wouldn’t recognize that this structure existed in the material just by inspection. Ri ore rn ah “Ae v's pil nite 7 ee nih slibose t arn — ms mea . HM Opt ‘. ai a es ae sinw | ret (a gnlvedt sate ds ‘ght Soyer msc) Youn ot "2" Wi’ ads’ rar valaislir it ieteed WRN TGE MINIT * in * a hb tat Far ie dks ‘ap ied iL Lf 5 "i ‘ ‘snltag SWS il ! suited sata m esa iti ati 7G iy ui ore rloga’ ppl es pent 2 ie 4 host bul = nf + Thats ial die 24) bal DYNAMICS IN RECENT MARINE BENTHONIC OSTRACODE ASSEMBLAGES IN THE LIMSKI KANAL (NORTHERN ADRIATIC SEA) HENNING UFFENORDE Geol.-Palaont. Institut, Géttingen, Germany ABSTRACT The population dynamics of twelve mediterranean ostracode species have been studied on the basis of 140 quantitative sediment samples from the euhaline clayey silt bottom of the Limski Channel (yugosl. Limski kanal). Samples were taken at monthly intervals between September 1967 and October 1968. The species belong to autochthonous benthonic assemblages inhabiting a biotope with a low energy level. Although all are perennial forms, the population dynamics show remarkable temporal differences, ranging from aperiodic or (?) long-periodic to seasonal periodic and short-periodic with all transitions. As most perennial! species with distinct seasonal life-cycles hatch in fall and winter, it is assumed that food supply is one of the major controlling factors and that water temperatures are always above the thermo- pathic level. Species with long-periodic life-cycles have not been observed. KURZFASSUNG Zwolf mediterrane Ostracoden-Arten wurden hinsichtlich ihrer Popula- tionsdynamik untersucht. Grundlage dafiir bildeten 140 quantitative Sediment- proben von den euhalinen, tonigen Silt-Béden des Limski kanal. Die Probenahme erfolgte monatlich von September 1967 bis Oktober 1968. Die Arten gehoren autochthonen benthonischen Assoziationen an, deren Biotop hinsichtlich der Wasserbewegung gering exponiert ist. Obwohl es sich um Dauerformen handelt, zeigt ihre Populationsdynamik erhebliche zeitliche Differenzierungen, die von aperiodischer oder (?) langperiodischer bis zu_ saisonal-periodischer und kurzperiodischer Dynamik reichen. Da die meisten Dauerformen mit deutlich saisonalem Lebenszyklus im Herbst und im Winter schupfen, wird angenom- men, da8 das Nahrungsangebot einer der bestimmendon Okofaktoren ist und da8 die Wassertemperaturen stets tiber den Thermopathie-Niveaus der Arten liegen. Arten mit langpriodischem Lebenszyklus wurden nicht beobachtet. INTRODUCTION Studies on the dynamics of ostracodes living on the sublittoral sea floor are rare. In view of the comparative domination and importance euhaline sublittoral ostracodes have, we must acknowledge a pronounced deficiency of research in this field. Some reasons for this deficiency are: 1. The normally very limited population density!, especially in off-shore regions. 2. High variations in species abundance which become more obvious with increased exposure to water movement. 3. The drifting of dead as well as live ostracodes, especially in the more exposed coastal regions. 1 The term ‘population’ is used here in common with Schwerdtfeger (1968, p. 18) for “the totality of individuals of one species in a defined area” (in free translation). 148 H. UFFENORDE 4. The rareness of observation areas that are euhaline and easy to reach during all seasons. The complexity of the mutual influence of the ecological factors. The complexity of the ostracode distribution patterns. The difficulties involved in the breeding of euhaline ostracodes. The lack of quantitative sampling techniques. 9. The tedium and logistic problems of seasonal studies. Starting points to overcome these difficulties lie: I. In the choice of an area of investigation, 1. with a relatively high population density, onnn 2. with little variation in population abundance, 3. with a minimum of allochthonous individuals, 4. which reflects the conditions of the sea on a minor scale in near-shore areas, 5. in which life underlies conditions that are close to a surveyable model. Il. In collecting data on environmental factors, which might have an influence on spatial and seasonal abundance, coinciding with the ostra- code sampling. III. In developing a proper sampling technique. These starting points in mind, a student group from the Institute of Geology and Paleontology, University of Géttingen, carried out a sedimen- tological and microfauna] research program, including oceanographic studies, in the Limski kanal. This program was initiated, organized, and directed by Dr. D. Meischner, who is to be gratefully acknowledged for his help along with my colleagues Drs. C. H. v. Daniels, D. Fiitterer, J. Paul, and J. Schneider. The original research project was supported by the “Deutsche Forschungs- gemeinschaft” with grants Me 267/2,3,4,7,9, without which the study would not have been possible. I wish here to express my gratitude. The geographic position of the Limski kanal (Text-fig. 1) and its general thalassographic setting were repeatedly described by Vatova (1931), Vatova and Milo di Villagracia (1948, 1950), Hinze and Meischner (1968), v. Daniels (1970a, 1970b), Paul (1970a, 1970b), Uffenorde (1970, 1972), and others. For the results concerning the sedimentological investigations I refer to Paul (1970a, b), for those concerning the hydrographical investigations from 1967 to 1969 to v. Daniels (1970b) and Uffenorde (1972). The purpose of this paper is to give data on the seasonal variations in population dynamics of 12 mostly euhaline, sublittoral ostracode species, data which allow one in some cases to estimate the duration of development and the sex ratio, and further to show in a few examples the range of modification in the life-cycles of marine Ostracoda. This information might be useful for the understanding and interpretation of mediterranean ostracede faunas, whether they belong to biocenoses or autochthonous taphocenoses. Dynamics oF OsTRACODE ASSEMBLAGES IN ADRIATIC 149 Text-figure 1. Map showing area of investigation and position of sampling stations. A first account of the variation in the total ostracode abundance as well as on the population dynamics of 14 species was given by me on the basis of a study of 98 samples (Uffenorde, 1972). Forty-two (42) additional samples were examined in order to verify the earlier results and to get more data concerning the population dynamics of some other species. The seasonal variations of two of these species are briefly discussed here. For references on this subject see Theisen (1966, pp. 254 ff.) and Uffenorde (1972, p. 37). It is also to be noted that the special terminology used here is in common useage with that of Schwerdtfeger (1968). MATERIAL AND METHODS One hundred and forty (140) sediment samples from 10 sampling stations were studied. The stations are shown on Text-figure 1. They are all situated in the median and inner part of the ria. The depth ranges from 6 ms at station 1 to 34 ms at station 5. The sediment is a clay-silt with a median grain size between 6 and 16 microns, mainly being agglutinated to fecal pellets (Paul, 1970a, p. 24). The samples were taken with an improved Krumm-grab (v. Daniels, Meischner and Uffenorde, 1970) at monthly intervals from September 17th, 1967 to October 12th, 1968. Each sample contained 27.3 cm* of the sediment surface and usually 2 to 3 cms of the uppermost layer. The laboratory treatment consisted of staining with rose bengal according to Walton (1952) modified by Lutze (1964), wet sieving on a screen with a mesh-size of 63 “s, and dry picking. 150 H. UFrFreNnorpDE The criterion for being counted as a living ostracode, was the presence of the complete soft body. The rose bengal staining proved to be a helpful method to discover living individuals, particularly the larvae. As the populations, even of the relatively common species, do not exceed 2 specimens per 10 cm’, a study of the seasonal] distribution of their instars is only possible with the assumption that the area studied is fairly homogenous with regard to the environmental factors. This being the case in the Limski kanal, we may summarize the counts from the sampling stations. Because among the 44 living species I found some have similar larval stages, only a few of the relatively common and easily distinguishable species give information on population dynamics. As to be expected in an environment of a low energy level, instars within the same developmental stage vary only slightly in their dimensions. Therefore the developmental stage of the instars studied were identified by measuring length and height of the carapaces. Because of the methods used, no complete life-cycle was found. Usually the eggs, the nauplius larva, and the A-7 stage were washed away during the sieving; the latter stage may be present but only in small number. For further details concerning the methods used see Uffenorde (1972, pp» léett.)): POPULATION DYNAMICS According to Theisen (1966, p. 254) most marine ostracodes seem to be perennial forms. As this statement is based on data concerning euryecological, especially mixohaline Ostracoda studied by him and other authors, we should expect a high majority of perennial forms in a mainly stenecological, euhaline environment. This indeed proved to be true for the species studied in the Limski kanal. The term ‘perennial’ is used here in the sense of Alm (1916), Theisen (1966), and others. According to their definition, perennial forms occur during the whole year as adults and larval stages or in larval stages. Between the perennial forms, however, a differentiation in the seasonal distribution can be observed. Five (5) groups of perennial forms may be distinguished: 1) Species which seem to be aperiodic. Five species — so far as we can see from a collecting period of 14 months — show no periodic distribution. Cytherella sp. (TYext-fig. 2) (for description see Uffenorde, 1972, p. 50) which is closely related to the fossil species Cytherella vulgata Ruggieri, 1962, is found under normal conditions both as juveniles and adults. During May, June, and August until October, 1968, the population density was extremely low. In an area of 273 cm* only a few specimens were present, in September there were none. This apparent, not real, low abundance is caused in part by dragnet fishing in April. Because of this fishing method, Dynamics oF OsTRACODE ASSEMBLAGES IN ADRIATIC — one specimen female adult male A « La = ee os — A-! = Si = a = A-2 = ag a = A-3 = — == — A-4 = = = — — A-5 ira | f= = A-6 |_| B = AT a os - Shae A-8 = BB = mee 10 He 12s ; 3) 4. ; 6. he 8. oF 1967 {968 Text-figure 2. Cytherella sp. Seasonal distribution of instars, females, and males on the basis of 215 living specimens. 152 H. UFFENORDE the sediment of the eastern and western regions of the inner Limski kanal is stirred up and displaced, burying the ostracode fauna. It takes approximately two months for the ostracode fauna to reconcentrate on the sediment surface. The reason for the decline in August is unknown. Cytherella sp. was the only species observed with ovigerous females throughout the year. A maximum of eight eggs was observed, four on each side of the individual. The ratio between ovigerous and non-ovigerous females was on the average about 4 to 1, the sex-ratio nearly five females to four males. Propontocypris setosa (G. W. Miiller, 1894) (Text-fig. 3) is included in this group, too, although the generation that passed the larval stage A-6 from November to February appeared in higher number. This generation seems to have a relatively high mortality rate in the later larval stages so that no more adults are found. Unfortunately this development is concealed by the destruction of the microenvironment by fishing after the April sampling as well. Pseudopsammocythere similis (G. W. Miller, 1894) and a Loxoconcha species, which is closely related to the fossil Loxoconcha dertobrevis Ruggieri, 1967, seem to belong to this group as well as: Carinocythereis antiquata bairdi (Uliczny, 1969) (Text-fig. 4), although its population density is so low that there are no readings for many of the larval stages. The average sex-ratio is about four females to one male. Species with long periodic life-cycles have not been found in the area studied. 2) Species with long periodic dynamics (?) but short life-cycles. Cytheropteron rotundatum G. W. Miller, 1894 (Text-fig. 5) possibly repre- sents a species with a long periodic population dynamic, the undulations of which last longer than the collecting period and obviously take some genera- tions. Larvae were common in September, 1967, and October, 1967. It seems that a high mortality rate reduced their number so that only a few adults were found in fall 1967. The larvae of the winter generation were, therefore, smaller in number, those of the spring generation were again smaller in number. This interpretation, as well as the dotted line drawn between the winter and the spring generation, tentatively indicating the general trend of the growth rate, should be taken with caution. More materia] needs to be sampled and studied before we may reach any definite conclusions. 3) Species with distinct seasonal life-cycles. Six species have revealed a distinct seasonal population change. Leptocythere ramosa (Rome, 1942) (Text-fig. 6) is one of the best examples for this group. From September, 1967, until March, 1968, the generation I was observed, consisting, with two exceptions, of only adults. The average sex ratio was about four females to one male. Generation II first appeared in limited number. The stage A-7 reached its highest abundance in March, reaching maturity first in July. For Cytherois sp. C, another good example, see Uffenorde (1972, p. 103). Four species with lower population densities also seem to produce only one generation per year. DyNAMICs OF OsTRACODE ASSEMBLAGES IN ADRIATIC BEL cses A2 MH _ A-3 A-. m a5 A-7 —_ oF 0 = it: 1967 12. e 1 | a | Zz (6 = 4. 3); 1968 = One specimen 6. = wo 153 10. Text-figure 3. Propontocypris setosa (G. W. Miiller, 1894). Seasonal distri- bution of instars on the basis of 398 living specimens. 154 ~_H. UrFENoRDE — one specimen | Bault female OO uN male ee ae te OS ee - = A-l — = _ -:lUl A-2 = = => SS —_- st A-3 = = | A-4 —_ = — = g = A-5 — = |_| | A-6 Zs = = = @ @ Bg _ 9 10 ale 2 il. Db. a: Lee 5 6. ie 8. 9. 10. 1967 1968 Text-figure 4. Carinocythereis antiquata bairdi (Uliczny, 1969). Seasonal distribution of instars, females, and males on the basis of 143 living specimens. With Hiltermannicythere turbida (G. W. Miiller, 1894) (Text-fig. 7) first individuals of A-6 appeared in January, and became adults in July. Judging from the long period of occurrence of instars of A-6, it may be assumed that the species has a hatching period of more than half a year. Pterygocythereis jonesii (Baird, 1850) (Text-fig. 8) passed the stages A-6 and A-5 in winter and reached adulthood from July onwards, the average growth rate being approximately one instar per month. A similar life-cycle is shown by Cytheridea neapolitana Kollmann, 1960 (Text-fig. 9). Basslerites berchoni (Brady, 1869) (Text-fig. 10) develops later in the year, passing the middle larval stages during summer, fall, and winter and being adult from September onwards. 4) Species with weaker seasonal undulations in abundance. A less distinct seasonal population change was observed with Cytheroma variabilis G. W. Miiller, 1894 (Text-fig. 11) which has higher numbers of larvae in winter and more adults from March to July. During the latter time a few males were found, and it is believed that during these months copulation takes place. 5) Species with short periodic dynamics. Shorter undulations may be seen in the following histograms of Lefto- cythere bacescoi (Rome, 1942) and Cytherois aff. C. fischeri (Sars, 1866). Dynamics oF OsTRACODE ASSEMBLAGES IN ADRIATIC 155 With Leptocythere bacescoi (Text-fig. 12) three or perhaps four genera- tions developed during the collecting period. There was an undulation between a higher proportion of older larvae and adults (in September, 1967, February and August to October, 1968) and younger larvae (in November, 1967, March, 1968, and July, 1968). The samples disturbed by fishing unfortunately prevent a clearer picture. This is also true for Cytherois aff. C. fischeri (Text-fig. 13). In this histogram a second hiatus is visible. Nevertheless two generations seem to exist. Most of the species studied are perennial forms. Species with strictly seasonal occurrence of adults and larvae are rare in the biotope studied and data are very limited. Cytherois frequens G. W. Miller, 1894 (Uffenorde, 1972, p. 101) is one of the relatively more common species, the occurrence of which is seasonally restricted. Larval stages were observed between December and July, adults between February and July. Until resting eggs are found, the seasonal occurrence might also be explained by a seasonal immigration from a_ neighbouring habitat. CONCLUSIONS In summarizing the results of this brief study on the seasonal distribution of 12 marine ostracode species, the following conclusions may be drawn: 1. In accordance with the results of studies done by Elofson (1941, pp. 383 ff.), Theisen (1966), and others in northern European marine environments most benthonic ostracode species were found throughout the year as adults and as juveniles or as juveniles. That means in practice that an adequate sample (in the sense of Kaesler, 1966, p. 23) taken at any time of the year, gives correct information for presence/absence records, if we take all indi- viduals (adults and juveniles) into account. 2. Even in a biotope of a low energy level, as the soft bottom of the Limski kanal, certain temporal differences are visible between the perennial ostra- codes. The dynamics of the population differ considerably in the course of the year. In consequence, frequency counts have to be done seasonally if one intends to get an adequate representation of the complete living ostracode fauna of a marine environment (e.g. Wagner, 1957, p. 107); this applies to biotopes of high as well as low energy levels at least near- shore. 3. Within one and the same ostracode assemblage a wide spectrum in temporal abundance may occur from an obviously aperiodic to a distinct periodic population dynamic. The ostracode associations — although as a whole being in an equilibrum with the environment — react in its elements in different ways according to their special situation in the ecosystem. 4. The more or less distinct periodical abundance dynamic may either be longperiodical, seasonal, or shortperiodical, which applies to distinct genera- tions as well as the total amount of individuals from different generations living at the same time. Species with long-periodic life-cycles, as for instance Philomedes globosus (see Elofson, 1941, pp. 396, 397), have not been observed. 156 A-2 tentatively indicates the border trend of the growth rate. H. UFFENORDE = One specimen 9. 10. N 1967 12. — = re lM |, = 26 3 4. 5: 6. Ue 8. sh) le: 1968 Text-figure 5. Cytheropteron rotundatum G. W. Miller, 1894. Seasonal distribution of instars on the basis of 263 living specimens. The dotted line between two generations and the general Dynamics oF OsTRACODE ASSEMBLAGES IN ADRIATIC 157 — one specirnen {AS <5 fa female << } fa / Leet a OS oa iat adult ole II I E i BeBe. _ BH oo mw & Na = a faz a =s- A-2 * c _ _ A-3 - — |_| = a | a — |_| — = A-5 Pe se — [i =— A-6 a a = — -_ DNR et =e = F sl g. 10 11 12" il; 2. 3 4. 3). 6 7 8 9 10. 1967 1968 Text-figure 6. Leptocythere ramosa (Rome, 1942). Seasonal distribution of instars, females, and males on the basis of 226 living specimens. The dotted line indicates the border between generation I and generation II and the general trend of the growth rate. 158 H. UFFENORDE — one specimen L< female =) adult male ee Sa eee ee ee eee a I Il A a a | i—| = —_ — = == t=) = ose A-1 — ° O ; — BS A-2 — e e | | ss A-3 as ; BG « A-4 — os — = — A-5 s e —_ = = = = A-6 ae -« & == @ —-_ - 9. 10 11 125 il. Qe 4}. 4. 5). 6. 7 8 9. 10 1967 1968 Text-figure 7. Hiltermannicythere turbida (G. W. Miller, 1894). Seasonal distribution of instars, females, and males on the basis of 89 living specimens. The dotted line indicates the border between generation I and generation II and the general trend of the growth rate. = one specimen & female oO adult sie I II A = = = = = .° = = — os A-1 a. = A-2 a A-3 ON = A-4 fie Sete cd aa A-5 fvepntl antl aoe cal A-6 °° | i -— 9 © th @ 4 DB 88 & 9S 6 eee 1967 1968 Text-figure 8. Pterygocythereis jonesi1 (Baird, 1850). Seasonal distribution of instars, females, and males on the basis of 52 living specimens. For dotted line see explanation Text-figure 7. Dynamics oF OsTRACODE ASSEMBLAGES IN ADRIATIC 159 — one specimen I II A -— = = - fe = A-| e. a A-2 i : = a Aas Oris : | os ea al = A-5 Kone = = A-5 Be” = — Lat ea —_ Bewar All. i pe, OS Oe eB 8: 1967 1968 Text-figure 9. Cytheridea neapolitana Kollmann, 1960. Seasonal distribu- tion of instars on the basis of 33 living specimens. The dotted line indicates the border between generation I and generation II. — one specimen —— eel rt } : ee A-1 a” BD: vee cttw ms os ae A-2 = et 2 A-3 oe —-_ = A-6 _ = ae co = Wes: a a Be es A-6 = aed a Gay idee a1 ize wie 2 ae See. 7 Bee eee a0: 1967 1968 Text-figure 10. Basslerites berchoni (Brady, 1869). Seasonal distribution of instars on the basis of 77 living specimens. For dotted line see explanation Text- figure 9. 160 H. UFFENORDE A-6 = 6hCU@ SI t,t 1967 == one specimen - CX 3. 6. 1968 adult = female male Text-figure 11. Cytheroma variabilis G. W. Miller, 1894. Seasonal distri- bution of instars, females, and males on the basis of 352 living specimens. Dynamics or OstTRACODE ASSEMBLAGES IN ADRIATIC 161 — one specimen A | A fees Sa A-3 = = A-, = A5 = A7 & 9 10 1, 1967 2. 8 2. 5. 1968 6. = Text-figure 12. Leptocythere bacescoi (Rome, 1942). Seasonal distribution of instars on the basis of 352 living specimens. 162 A-2 H. UFFENORDE — = 63 microns. Dr. A. Lieubau: Cytheropteron needs more than one year for a generation. Dr. Uffenorde: No, with Cytheropteron rotundatum it seems that we have to distinguish between a short change of the generations and a stronger long ranging natural undulation of the whole population. I estimate the duration of development at five to seven months, roughly. As my study only comprised a period of 14 months this was too short a time to evaluate the long periodic undulations of this species. - -. $¥A oa Hliae, ©, ore Y wis nner. 5. thoes — itigh uf anl he pek TO 98 gait cia o itaww be fag Cima wie sea rail, a At at fre’ Pe paBeva? daga. V4, latvatacn ied Ivf ; . ' ; aT mj” ane ah hau « ved ‘oy * VajAW Ne HW, ay ee AME tak? Boye ass Sail qete PEW 1a epee EN re a i ‘ ! y ’ nd bbe hagiales ie gret oie) vba vate Oe Oe : f fio Greed! One Cuenta } immi wil’ a anv a vay ia aT mir a Taser ite vuley be th eae ‘ or * % inmite tot? oft: tha bs stu ¥ vat “aye ahike ae wa ' ~ ; 468 in~iee s anys <2 1 mas, qe. oleae J ’ he rola)’ ais y atrel the rf ey Kt tila de? ut ran | Wee oe eo gq | ; 16 nol +) oF ia) Kees 1 st > VARIATIONS IN FRESH-WATER OSTRACODE POPULATIONS FROM LAKES IN ST. LOUIS COUNTY, MISSOURI Dorotuy J. Ecnors, L. GREER Price, anD Mary ANN RAFLE Washington University ABSTRACT During 1962-1963, seasonal collections of living fresh-water ostracodes were made from six lakes in St. Louis County, Missouri. At that time, the effects of seasonal changes on the occurrence of species and relative abundances of young and mature forms were noted. Now, nearly ten years later, four of these lakes have been sampled during the winter, spring and summer months, and the conditions noted previously were recorded. The combined ostracode fauna of the lakes sampled consisted of species of Cypria, Candona, Potamocypris, and Cypridopsis. The compositions of the ostracode faunas collected in 1962-63 and 1971-72 show a net increase in faunal diversity and exhibit distinct seasonal variation. VARIATIONS DANS LE POPULATIONS D’OSTRACODE D’EAU DOUCE DANS DES LACS DU COMTE DE SAINT-LOUIS DANS LE MISSOURI RESUME Pendant l’année 1962-1963, on rassembla a différentes saisons des ostracodes d’eau douce yivants qui avaient été péchés dans six lacs du comté de Saint- Louis dans le Missouri. On enregistra chaque fois les effets des changements dus aux saisons sur la présence des especes et sur l’abondance relative des spécimens jeunes et adultes. Maintenant, prés de dix ans plus tard, on a ras- semblé des spécimens obtenus dans quatre de ces mémes lacs pendant les mois d’hiver, de printemps et d’été et on a noté a nouveau le conditions déja observées auparavant. La faune ostracode rassamblée dans ces lacs se composait d’espéces de Cypria, Candona, Potamocypris and Cypridopsis. On a constaté qu’il y avait une augmentation nette dans le diversité des faunes ostracodes recueillies en 1971-72 comparées a celles de 1962-63, ainsi qu’une variation saisonniére marquée. INTRODUCTION Although studies on Recent fresh-water ostracodes have contributed con- siderable information to the overall knowledge of ostracode life history and the variables that determine their distribution, many more field observations on permanent, natural, or man-made lakes are needed for meaningful interpreta- tions to be made. The present investigation was undertaken to augment the information obtained from a similar study completed nearly ten years ago. During 1962-63, R. P. Frey and D. J. Echols made seasonal collections from six lakes in St. Louis County, Missouri. At that time they hoped to determine (1) whether genera and species of ostracodes vary seasonally, (2) whether seasonal changes affect their relative abundances, (3) whether the laying of eggs and the development of young are related to seasonal changes, and (4) whether environmental conditions influence their geographical distribu- tion. Although results of this study did not answer all of the questions asked, they were significant enough to warrant a reinvestigation of at least some of the collecting sites. 168 D. J. Ecos, L. G. Price, anp M. A. RAFLE i 4 gy < iy misso¥ Pe mbrok %y x : Wabash a - vA ea Coeur i / ILLINOIS MISSOURI / 2 / xo / “a a / = - Forest Park e ° xX / i Qok Knoll | ee | / ST. LOUIS 3.5 miles | i \ \ S N N » SS \ NX FIGURE | Collecting sites In this second study, we hoped not only to correct operational error and eliminate interpretive bias, but also to answer two other important questions, namely the relationship between faunal variety and the age of the lake, and the effect of man’s induced environmental changes on the faunal composition. Text-figure 1 is a schematic map of St. Louis and vicinity which shows the approximate locations of the lakes from which collections were made. For the present study, four of the lakes sampled in 1962-63 were recollected during the winter, spring and summer months. Samples of 3 to 4 cubic centi- meters of material were collected by means of a conical 200 mesh plankton net at various stations and depths within each Jake. When the collections were made in 1962-63 and again in 1971-72, the following conditions were noted: (1) the general appearance of the lake (i.e. size, water level, amount and distribution of aquatic vegetation), (2) temperature, (3) pH, and (4) bottom conditions. Table I summarizes the physical conditions recorded from the three lakes in which live standing crops of ostracodes were recovered and the relative seasonal abundances of the species identified. The fourth lake col- lected was Creve Coeur lake, a natural cut-off meander of Missouri River, and 169 FRESH-WATER OstTRACODEs Missouri — ————————— fuOUUOD=9 ¥OUT-SL ‘UBpUNqe=y (Té6gT B1AB\) BUFP ——r —seiBus STIGALOWB Og (QLLT 29TTINW *4°0) UnpyA S~Ssdoppadny (OegT euranp) Gopupeyzydo wyadAg =) JJOH Busqingns O06T uuBujNney BpPEpneo 7) pnw oTUBsIO HOUT PUN % 4TTS TeFte7eW Woy og woutTssne BUulST Beutssne Buuley (pesBatoep) BuueT UOFyBYedaA DTYZunby ‘BUST auoN 6°L T'6 TL Tg Hd Ge (epBsatqzuec) aunjetsdusy 19784 Of-t O&-S yqdaq 19384 (Ewe *bs) Bety soBjang 0 ac6 T u8T-8 “ 000‘ 002 HSVdVaM 000*SL DIOUdNad HSVEVA TION AVO GHOddNad I WIavi 170 D. J. Ecuors, L. G. Price, anp M. A. RAFLE contained no living ostracode populations in either 1962-63 or 1971-72, al- though corroded carapaces of Candona and Potamocypris were found. This appears to be one case in which man’s environmental changes have directly affected the ostracode populations. Urbanization within the drainage basin has increased the sediment yield, and the great quantities of suspended silt and mud, as well as the continuing lack of organic material, make this environ- ment unfavorable for the development of a diverse aquatic community. The composition of the ostracode fauna collected from Oak Knoll pond in 1962-63 and 1971-72 shows a net increase in faunal diversity. SEASONAL DISTRIBUTION OF THE OSTRACODES Candona acuta Hoff, 1942, C. caudata Kaufmann, 1900 and C. suburbana Hoff, 1942, showed consistent seasonal distribution. They were conspicuously absent in the late spring and summer collections in both 1962-63 and 1971-72. A few immature forms were found in the fall collections, but the larger, mature forms, both males and females, were found only in the winter and spring collections. Females carrying eggs were most abundant in the December sampling. Hoff’s findings (1942) show that many species of Candona in Illinois vary in much the same way. Sharpe also noted in 1897 that the species of Candona which he studied were absent during the summer months and reap- peared in the fall. Although they occurred in varying abundances, mature and jmmature forms of most of the other species were found in at least one collection every season. Cypria ophthalmica (Jurine, 1820), Brady and Norman, 1889, was by far the most abundant and cosmopolitan form found in the lakes studied in all sea- sons, with the peak productivity occurring in the spring. Not only was there an enormous increase in numbers but most mature forms and those gravid with eggs were recorded in April. That these are hardy forms is evidenced by the fact that they appeared early in the order of succession and are still a dominant form in Oak Knoll. No males were found in any of the collections. Potamocypris smaragdina (Vavra, 1891), Daday, 1900, is a common form, especially in permanent bodies of water. It is generally believed to have a seasonal occurrence in the spring, becoming most abundant in the summer months. Ferguson (1944), in collections from Round Lake in Forest Park, St. Louis, Missouri, concluded that P. smaragdina attains a primary peak of adult abundance in June, August, and October and is a spring-summer-fall form. He further stated that the normal seasonal population decline occurred in the month of November, and that the absence of adults from December to March suggests that this species passes the winter in the egg state. In contrast with this, both young and mature forms were found in our winter collections. In 1963 it was found in Wabash in all seasons, Pembroke in the fall and winter. In 1972 it was found in Wabash in the winter, spring and summer, and in Pembroke in the winter and summer. However, the relative abundances, the number of young, and mature forms gravid with eggs do suggest that it is predominantly a spring, summer and fall form but may be sporadic in occur- rence as reported by Alm (1916). This species is not yet established in Oak Knoll. FRESH-WATER OstTRACODES MIssourRI 171 Cypridopsis, which is generally considered one of the most common of North American ostracodes in permanent lakes, river backwaters and vernal ponds, was represented in our collections by the single species C. vidua (O. F. Miiller, 1776), Brady, 1867. Although it appeared in many of the collections, it Was present in surprisingly low numbers. This is particularly puzzling be- cause we have on many occasions collected random ponds for the purpose of laboratory culture and have found after a period of a few weeks to months great numbers of this species. Their scarcity in our field collections may possi- bly be explained by the dominance of Cyfria and the competition with that genus. Previous workers have shown that C. vidua is a summer-fall form (Hoff, 1943; Ferguson, 1944), present in limited numbers in April and May and very abundant June through October. Ferguson also stated that specimens reach- ing the adult stage in October could live through the winter into April, and Furtos (1933) reported occasional occurrences of C. vidua in February and March. In our collections, this species appeared oncz in February, became a prominent member of the fauna in May, and adults were most abundant during the summer months. We concur, therefore, with the observations of other authors that this species is a summer-fall form. In summary, the seasonal distribution of the faunas collected for this study shows that the species of Candona recovered from the Jakes are absent during summer months, present in small numbers in the fall, and attain full growth in the winter months. Cyfridopsis is generally absent in the winter months and present in increasing numbers from May through October. Cyfria and Potamocypris are most uniformly distributed throughout the year, both having a peak in abundance in the late spring. There is a definite relationship between faunal variety and the age of a lake. The appearance of Candona and Cypridopsis in the 1971-72 collections from Oak Knoll pond is a significant increase in diversity over the ten year span. No change was noted in the bottom material from 1962 to 1972. Hoff (1942) stated that ostracode distribution appears to be random as far as the type of bottom is concerned. This is found to be the case, as changes in distri- bution appear to be more a function of time than of bottom type. REFERENCES Alm, G. 1916. Monographie der Schwedischen Susswasserostracoden. Zoolog. Bidrag Uppsala, 4, pp. 1-249. Ferguson, E. 1944. Studies on the seasonal life history of three species of freshwater Ostracoda. American Mid. Nat., 32, pp. 713-727. Frey, R. P. 1963. Studies on some recent freshwater ostracodes of Saint Louis County, Missouri, Unpublished MA thesis, Washington University, St. Louis, Missouri. Furitos, N. C. 1933. The Ostracoda of Ohio. Ohio Biol. Sur., 5, pp. 413-524. V7 D. J. Ecuots, L. G. Price, anp M. A. RAFLE Hoff, C. C. 1942. The ostracods of Illinois, their biology and taxonomy. Illinois Biol., Mon. 19, (1 & 2), pp. 1-196. 1943. Seasonal changes in the ostracod fauna of temporary ponds. Ecology, 24, pp. 116-118. Mason, C. B. 1971. The origin and history of Creve Coeur Lake. Unpublished MA thesis, Washington University, St. Louis, Missouri. Needham, P. R. 1940. Trout streams. Comstock Publishing Co., Ithaca, N.Y., 233 pp. Sharpe, R. W. 1897. Contribution to a knowledge of the North American freshwater Ostracoda included in the families Cytheridae and Cyprididae. Bull. Illinois St. Lab. Hist., 4, pp. 414-484. 1918. The Ostracoda. Ward and Whipple, Freshwater biology, John Wiley and Sons, New York, N.Y., pp. 790-827. Dorothy J. Echols, L. Greer Price, Mary Ann Rafle Department of Earth Sciences, Washington University, St. Louis, Missouri 63130 DISCUSSION Dr. G. Hartmann: Could you explain your identifications of species of Candona? Mr. G. Price: I think that probably it was C. acuta and perhaps C. suburbana. Dr. Hartmann: You see there are different types of Candona, some with maxi- mum development in the summertime, some maximum jn winter. Dr. Sohn: Did you find males and females of your candonas? Mr. Price: Yes, we did, but we did not with the other genera. THE RELATIONSHIP BETWEEN OSTRACODA AND ALGAE IN LITTORAL AND SUBLITTORAL MARINE ENVIROMENTS R. C. WHATLEY Universidad Nacional de La Plata, and University College of Wales, Aberystwyth, Great Britain D. R. WALL Burmah Oil Co. of Australia ABSTRACT The importance of algae in influencing the distribution of Ostracoda has been demonstrated by such workers as Colman (1940), Dahl (1948), Wieser (1952-1959), Chapman (1955), Ohm (1964), Reys (1963), and latterly by Hagermann (1966, 1968, 1969), Whatley and Wall (1969), and Williams 1969). : The following statistics further emphasize the importance of this relation- ship. In a recent study of the podocopid Ostracoda of Cardigan Bay in the southern part of the Irish Sea, involving several hundreds of samples, 95% of the living ostracodes encountered were from samples of littoral and sub- littoral algae. The remaining 5% of live individuals were from a much larger number of samples from sediments of various types, both from the littoral and sublittoral and from offshore stations. The present paper is in the form of a semi-quantitative and largely sea- sonal study of Ostracoda recovered from various species of algae at a number of stations along the Welsh Coast. A total of 23 species of podocopid Ostracoda were recovered from a total of more than 29 species of algae. (In some cases it was not possible to identify various members of the Rhodophyceae, which were, therefore, collected and considered together at this level.) The eulittoral and sublittoral are treated separately and conclusions are drawn concerning the significance of seasonal changes in the specific nature and population structure of the ostracode faunas of the two and of seasonal faunal migrations between them. It is further concluded that the nature of the relationship between Ostracoda and algae is a most complex one but that the major factors governing this relationship include: the morphology of the plants and the nature of the shelter or protection which they afford from physical and biological pressures; the position of the plant, both macro and micro- environmentally within the zones studied; whether the relationship to food supply is direct or indirect; the type and amount of sediment enclosed within the plant; and the seasonal development of the plant. The final part of the paper deals with a comparison of the present results with those of previous workers within this field and with similar studies which one of the authors (RCW) is currently undertaking along the coast of the Argentine Republic. RESUME L’importance des algues quant a leur influence sur la répartition des Ostra- coda a été démontrée par des chercheurs tels que Colman (1940) ; Dahl (1948) ; Wieser (1952, 1959); Chapman (1955); Ohm (1964); Reys (1963); et plus récemment par Hagermann (1966, 1968, 1969); Whatley et Wall (1969) et Williams (1969). Les statistiques suivantes mettant ]’accent sur l’importance de la relation entre Ostracoda et algues. Dans une récente étude sur les Ostracoda Podocopida de la Baie de Cardigan dans la région sud de la Mer d’Irlande, étude englo- bant plusieurs certaines d’exemplaire échantillons, 95% des ostracodes vivantes trouvés provenaient d’échantillons d’algues littorales ou sublittorales. Les 5% restant individus vivants provenient d’un plus grand nombre d’échatillons de sédiments de types variés, littoraux et sublittoraux, et de lieux éloignés du Rivage. _ Warticule suivant est une étude semi-quantitatif et pour la plupart saison- nier sur des ostracodes en provenance d’espéces variés effective d’algues sur 174 R. C. WuHaTLey anp D. R. WALL un certain nombre de staticns de la céte galoise. Un total de 23 espéces de Podocopida fut recueillie sur un total de plus 29 espéces d’algues étudiés. (Dans certains cas il ne fut possible d’identifier plusieurs membres des Rhodophycaea qui furent, par cette raison, rassemblés considéreés ensemble a ce niveau). L’eulittoral et sublittoral sont traités séparément et des conclusions sont tireés quant a la signigication des changements saisonniers de la nature spéci- fique et de la structure de la population des faunes ostracodes des deux et des migrations saisonniers de ]a faune entre elles. Un conclusion plus avant que la nature de la relation entre les Ostracoda et les algues est extrémement complexe mais que les facteurs les plus importants gouvernant cette relation comprennent: la morphologie de la plante et la nature de |’abri ou protection quel tire des pressions physiques et biologiques; la position de la plante, des macro et microenvironnements a l’intérieur des zones étudiés; si la relation avec l’apport de nourriture est direct ou indirect; le type et la quantité de sédi- ments que contenant la plante et le developpment saisonnier de la plante. La partie finale de l’etude traite des résultats actuels comparés a ceux de cherchaurs anteneurs et aux études semblantes que l’un des auteurs (RCW) est actuellment en train d’effectuer sur la cote de la République Argentine. RESUMEN La importancia de las algas como factor influyente sobre la distribucién de los Ostracoda, ha sido demostrada por varios autores; Colman (1940), Dahl (1948), Wieser (1952, 1959,); Ohm (1964), Reys (1963); y mas recientemente por Hagermann (1966, 1968, 1969), Whatley y Wall (1969); y Williams (1969). Las estadisticas siguientes enfatizan atin mas la importancia de la relacion entre Ostracoda y algas. En un estudio reciente de los Ostracodos podocopidos de la Bahia de Cardigan, en la parte meridional del Mar de Irlanda, con- siderando varios centenares de muestras, un 95% de los Ostracodos vivientes fué encontrado en muestras de algas litorales o infralitorales El 5% de in- dividuos vivos restantes fué obtenido a partir de un numero mucho mayor de muestras, de sedimentos de varios tipos, tanto litorales como infralitorales, y de estaciones de mar abierto. El presente trabajo tiene la forma de un estudio semi-cuantitativo, y mayormente estacional, de los ostrdacodos recuperados en muestras de varias especies de algas en un numero de estaciones a lo largo de la Costa de Gales. De un total de mas de 29 especies de algas estudiado, se recobraron 23 especies de Ostracodes podocépidos. (En algunos casos no fué posible identificar varios miembros de las Rhodophycaea, las cuales fueron entonces consideradas colecti- vamente a dicho nivel taxonémico). Los ambientes eulitorales e infralitorales son tratados separadamente extrayéndose conclusiones concernientes al significado de los cambios esta- cionales en la naturaleza especifica y estructura de la poblacién de las faunas de Ostracodos en ambos, asi como tambien a las migraciones faunisticas entre ellos. Se concluye, ademas, que la naturaleza de la relacién entre algas y Ostracodos es sumamente compleja, y que entre los factores principales que gobiernan esta relacién se incluyen: la morfologia de la planta, y la naturaleza de la proteccién que ésta brinda contra las presiones fisicas y biolégicas; la posicion de la planta dentro de las zonas estudiadas, considerando tanto su macro como su microambiente; si la relacién de alimentos es de caracter directo o indirecto; calidad y cantidad de los sedimentos incluidos dentro de la planta; y por ultimo, el desarrollo estacional de la planta. La parte final de esta publicacién esta dedicada a una comparacion de los resultados presentes con aquellos previamente obtenidos por otros autores den- tro de este campo, y con estudios similares actualmente en ejecucién por uno de los autores (RCW) a lo largo de la costa de la Republica Argentina. RELATIONSHIP OsTRACODA AND ALGAE 175 INTRODUCTION There have been relatively few studies concerning the faunas inhabiting seaweeds, and the majority of these have tended to neglect the Ostracoda. Colman (1940), Dahl (1948), Wieser (1952, 1959), Chapman (1955), and Ohm (1964) all studied the total fauna of algae and quoted the numbers of Ostra- coda occurring but generally did not identify the species concerned. Reys (1963) collected 37 live ostracode species from algae in the vicinity of Marseille and commented on the influence of the form of the algae on the ostracode popula- tions. Hagermann (1966) studied the total fauna of Fucus vesiculasus and identified 17 species of Ostracoda, and later (1968) discussed the general ecology of 14 species of podocopids from Corallina officionalis. The same author published a further, more detailed study of Hirschmannia viridis (O. F. Miller) in 1969, which was largely concerned with the relationship of the species to various green and brown algae. Whatley and Wall (1969) and Wil- liams (1969) published studies of Ostracoda from the coast of Wales which also treated the problem of the relationship between algae and Ostracoda. The importance of this relationship became apparent to us when, in a recent study of the Ostracoda from the southern Irish Sea, involving many samples from the littoral and Continental Shelf, we obtained 95% of the live individuals from algal samples which represented only a small percentage of the total number of samples studied. A general summary of the climatic, physiographic, and oceanographic con- ditions of the area under discussion have already been given in Whatley and Wall (1969). ACKNOWLEDGMENTS The authors wish to thank Dr. Lars Hagermann and Dr. John Whittaker for valuable discussions, and various colleagues at U.C.W., Aberystwyth, particulary Dr. John Haynes, Dr. Don Boney, and Dr. Max Dobson for much assistance. D. R. Wall was supported by a NERC Studentship during this work, and R. C. Whatley was supported during part of it by the Argentine Consejo Nacional de Investigaciones Cientificas y Técnicas, both are gratefully acknowledged. METHODS Algae were collected by means of placing a plastic bag over the plant and, detaching it in such a way as to obtain, not only the plant (roots were not included unless the term “holdfast’” is used), but also the immediately surround- ing water. Either in the lab or in the field, the contents of the bag were emptied into a large container and a 10% solution of formalin was added. After approximately 15 minutes, the sample was agitated vigorously and then washed with a strong jet of water. The contents of the container, from which the washed alga had been removed, were then collected on a 200 mesh/inch sieve, from which, after being allowed to dry, the Ostracoda were picked manually. The study was semi-quantitative in that each alga was identified and weighed wet, and at the stations where seasonal samples were taken, the same weight Was examined for each algal species at each collection, The imperfection of 176 R. C. WuaTLey anv D. R. WALL this method from a statistical standpoint is fully acknowledged by the authors, who realise that in terms of potential habitat, 50 grams of say the stem of Laminaria bears no relationship to an equal weight of densely intergrown Cladophora. Many of the algae are small or occurred sparsely in the area and this factor accounts for the low weights examined in the case of some species. In certain cases, after processing in formalin, the alga was examined under the microscope to ensure that all the Ostracoda had been removed. In not one case were ostracodes found on the processed weed. Additionally, several algae were picked manually without being put through the formalin process in order to contro] the results from the above method. This not only proved time con- suming but also yielded a consistently slightly lower number of ostracodes. Chemical and physical methods are as outlined in Whatley and Wall (1969). Only living ostracode specimens were studied. Individual ostracodes are considered live if they contain appendages. The usage of the terms “littoral fringe’, and “eulittoral’ and “sublittoral” zones is based on Lewis (1964); and the terms “upper” and “lower” sub- littoral zones are based principally on the observations of one of the authors (DRW). The “upper” sublittoral zone is defined as extending from just above E.L.W.S. to a depth of approximately 2 fathoms, the depth below which wave or surf action is presumed to exert negligible effect on the bottom fauna and the “lower” sublittoral zone as extending out from 2 fathoms to the limit of light penetration (or depth to which algal growth is supported). THE OSTRACODA The following 23 species of cytheracean ostracodes were recovered live from algae during the course of this study: Cythere lutea (Miller, 1785) Aurila convexa (Baird, 1850) Heterocythereis albomaculata (Baird, 1850) Hemicythere villosa (Sars, 1866) Carinocythereis antiquata (Baird, 1850) Hirschmannia viridis (Miller, 1758) Loxoconcha tamarindus (Jones, 1856) Loxoconcha rhomboidea (Fisher, 1835) Neocytherideis subulata (Brady, 1868) Leptocythere tenera (Brady, 1868) Callistocythere badia (Norman, 1862) Paradoxostoma ensiforme (Brady, 1868) Hemicytherura cellulosa (Norman, 1862) Microcytherura fulva (Brady and Robertson, 1874) Semicytherura striata (Sars, 1866) Semicytherura sella (Sars, 1866) Semicytherura ? concentrica (Brady and Norman, 1889) Paradoxostoma variabile (Baird, 1835) Paradoxostoma subelliptica (Wall, 1972) Paradoxostoma abbreviatum Sars, 1866 Paradoxostoma bradyi Sars, 1928 Paradoxostoma normani Brady, 1868 Paradoxostoma flexuosum Brady, 1868 RELATIONSHIP OsTRACODA AND ALGAE V7 TAXONOMIC NOTE It is thought necessary to explain the usage of the following: Semicytherura? concentrica. The material we have, together with the original, may in fact represent instars of Hemicytherura cellulosa. Dr. John Whittaker is working on this problem currently. Loxoconcha tamarindus; this species is removed from Hirschmannia and returned to Loxoconcha because the antennae are long and slender and have six podomeres and the penis is very different from that of H. viridis and more similar to Loxoconcha. The hinge, although more similar to that of Huirsch- mannia is here considered less important than the soft part characteristics mentioned above. Paradoxostoma subelliptica Wall, nom. nov. is for P. hibernicum sensu Sars (1928) which is not conspecific with the original material of Brady (1868). The majority of the species are well known as being phytal, whilst others such as Hemicythere villosa and Loxoconcha rhomboidea are also frequently encountered in other environments. The occurrence of such species as Neo- cytherideis subulata, Leptocythere tenera and Carinocythereis antiquata living amongst algae, albeit rarely, is unusual. COLLECTING LOCALITIES Algal samples were collected at the following stations: From the ‘lower’ sublittoral zone at stations 105, 106, 107, 108, 109, 110, 111, 556, 647, 931, 932, 939, and 940; from the ‘upper’ sublittoral zone, eulittoral zone and littoral fringe at stations 736, 745, and 933. A general description of the stations and of the algae and ostracod fauna collected from them is given below: Station 736: This is at Monk’s Cave, on the coast some 41%4 miles SSW of Aberystwyth (Lat. 52° 21’ N. Long. 4° 07’ W. and NGR 556748). At this station a study of the seasonal and areal variation of Ostracoda was made in the littoral and ‘upper’ sublittoral zones. Algae were collected from three intertidal rock pools, one in the littoral fringe, one in the eulittoral zone and one in the ‘upper’ sublit- toral zone on six dates (November 14, 1966; April 26, 1967; September 18, 1967; March 2, 1968; May 14, 1968; and August 9, 1968) during low water of Spring Tides. The shape, surface area and general expression of the plants and their seasonal growth and development, their growth situation relative to various critical tidal levels and their position within the pools, was found to exert a great influence upon their ostracod fauna. A detailed description of the locality, particularly of the three pools from which the samples were collected is given in Whatley and Wall (1969: 294- 296). Fucus serratus (75 grams wet weight) This large plant, with flat serrated fronds, was collected from each of the 178 R. C. WuaTLey anp D. R. WALL three pools although it occurs in greatest abundance on rock platforms in the upper part of the eulittoral zone, often as dense ‘mats’. a. From the pool in the littoral fringe, this plant was collected from around the periphery where it grew with its fronds partly submerged. Only 9 live ostracodes were collected during the 6 collections, and these in fact were from epiphytes, mainly Ectocarpus: Hemicytherura cellulosa one female, November 14, 1966 Aurila convexa one adult, April 26, 1967 Loxoconcha rhomboidea one female and one juvenile, September 18, 1967 Paradoxostoma variabile one juvenile, August 9, 1968 Heterocythereis albomaculata three females, August 9, 1968 The absence of Ostracoda on two of the collecting dates (March 2, 1968 and May 14, 1968) may possibly be related to the fact that on these dates the Fucus did not bear epiphytes. b. In the eulittoral, Fucus serratus only occurred on exposed rock plat- forms where, despite the common occurrence of epiphytes, ostracodes were not encountered. c. In the sublittoral, this alga occurs but rarely and generally lacks epi- phytes. Only five ostracodes were recovered: three adult P. bradyi on April 26, 1967, and further adult on May 14, 1968 together with one female L. rhomboi- dea. The small number of ostracodes recorded from this weed is probably a reflection of the fact that the large flat fronds afford little protection from turbulence or dessication and this is further aggravated by the fact that the plant frequently inhabits exposed parts of the sea shore. Hagermann (1966) has shown that in the @resund large numbers of Ostra- coda frequently occur on this plant. Colman (1940) quoted a mean number of only three specimens per 100 grams of damp weed, although his maximum is 1,480. Williams (1969) recorded variable numbers of ostracodes from this weed from localities around the coast of Anglesea. All these authors remarked on the correlation between high numbers of Ostracoda and the degree of epiphytic development. It would seem that the number of Ostracoda on Fucus serratus is influenced by whether or not the plant is growing in a sheltered situation. The relatively quiet waters of the @resund contrast with the exposed coast of Anglesea and Cardiganshire where very few ostracodes occur, although Wil- liams found relatively high numbers at Church Island in the more sheltered waters of the Menai Straits. Similarly the fluctuations in numbers at Wembury recorded by Colman, may also be a product of the situation of the weed. This factor can be seen in minuscule in our samples from Monk’s Cave. In the littoral fringe and in the sublittoral, the plant occurs in relatively sheltered situations and contained a fauna, albeit a meagre one. In the relatively more exposed eulittoral, the weed is barren of Ostracoda. Fucus spiralis (60 grams wet weight) This weed was collected from the littoral fringe and from the eulittoral only. At this station it always occurs in exposed positions and did not yield RELATIONSHIP OsTRACODA AND ALGAE 179 any ostracodes. It was noted that this species was, at certain times coated with a slimy secretion, presumably to inhibit the attachment of epiphytes, especially in its reproductive season. It is thought that this substance, together with the rather flat and open form of the weed, its lack in this locality, of epiphytes and its occurrence in exposed situations, could all be contributory factors to the absence of ostracodes. It is worthy of note that Colman (1940) recorded very few ostracodes from this species with a mean of 0.5 specimens per 100 grams and a maximum of 2. Similarly Williams failed to find any living Ostracoda on this weed in his more exposed localities, although a small number were present in the Menai Straits. Ulva sp. (30 grams wet weight) This flat membranous and fronded member of the Chlorophyceae was found in the littoral fringe and in the eulittoral zone, although in the latter not in sufficient abundance to enable a collection to be made. Specimens were collected from beneath an overhang in the pool in the littoral fringe. Many more ostracodes were encountered during the spring and summer than in the winter collections. Heterocythereis albomaculata, C. lutea, and H. viridis were virtually restricted to the spring and summer, whilst H. cellulosa, A. convexa, L. tenera. L. rhomboidea, and H. villosa occurred intermittently throughout the year. The small amount of shelter and protection provided by this weed seems to be compensated by the fact that it frequently occurs in sheltered micro- environments at some depth within the rock pools. Cladophora rupestris (35 grams wet weight) This dark green, densely tufted weed occurred commonly in rock pools in the littoral fringe and eulittoral. Whilst ostracodes were relatively abundant in the littoral fringe, in the eulittoral zone, this plant occurs in more exposed situations and yielded very few. During spring and summer it is particularly abundant near the surface of the pools in the littoral fringe, usually beneath a covering of Fucus spp. In the winter, however, it ‘dies back’ and loses its green colour. In the winter sample (November 14, 1966), only four live ostra- codes were recovered, but spring and summer samples yielded substantially more (141 on April 26, 1967, 115 on March 2, 1968, and 159 on May 14, 1968). The principal three species found in association with this weed were: H. viridis, C. lutea, and H. albomaculata. A further nine species occurred in smaller numbers. The tufted nature of C. rupestris, its occurrence in sheltered situations within the rock pools and the fact that it usually contains some amount of sediment, are obviously contributory factors to its providing a favourable habitat for Ostracoda. The increase in ostracode numbers in the spring may be correlated not only with the beginning of the repreduction of these animals with the commencement of favourable temperature conditions, but also with the renewed growth of the plant. 180 R. C. WuaT Ley anp D. R. WALL Wieser (1952) also noted the abundance of Ostracoda in association with this plant from the littoral of the Plymouth area and Williams (1969) also found substantial numbers inhabiting the closely related species, Cladophora sericea, from his Church Island locality in the Menai Straits. He recorded no less than 7,959 specimens from 100 grams of the weed. Enteromorpha clathra (30 grams wet weight) A green weed with long flat, unbranching fronds which, in some specimens, form a dense network. This plant occurs commonly in the littoral fringe and in the eulittoral during spring and summer but ‘dies back’ and becomes white in the winter. In the littoral fringe it occurs in shallow but sheltered pools often in association with C. rupestris. As with the latter, numbers of ostracodes present in the spring and summer are relatively high, whilst in the winter they are very low. The number of ostracodes recorded from E., clathrata is less than from C. rupestris but slightly more than from Ulva. This is pre- sumably a function of the form of these three algae, with Cladophora forming a dense and enclosed intergrowth, the flat fronds of Ulva providing few opportunities of attachment and relatively little shelter, and Enteromorpha being intermediate in this respect. The same three most abundant ostracodes as for C. rupestris occurred on this weed. Whilst Ostracoda were common in the littoral fringe, only four live individuals were recovered from the eulittoral samples in which zone the plant occurs in more exposed situations. Hagermann (1969) demonstrated the attraction of Enteromorpha to Ostra- coda (as well as to other animals). After removing all the fauna from nine stones, each with a 1 dm? patch of Enteromorpha, a faunal count was made of successive stones at regular intervals. After four hours there were 15 ostra- codes and pregressively more until after 120 hours, 815 specimens were counted, only slightly less than that of the control stone. This work affords a most convincing demonstration of the suitability of the microhabitat provided by this weed and of the migratory ability of benthonic Ostracoda. Williams (1969) recorded 176 specimens belonging to six species from 100 grams of the closely related E. compressa from Porth Swtan, Anglesea. Dictyoma dichotoma (18 grams wet weight) This member of the Phaeophyceae, with flat and rather limp dichotomous fronds in an open network, was collected from the littoral fringe and the eulittoral zone where, in both cases, it occurs in the shallower rock pools or in the shallow fringes of the deeper pools. From the littoral fringe one specimen of N. subulata was recorded, all the other samples being barren. Polysiphonia nigrescens (20 grams wet weight) This member of the Rhodophyceae, with thin branching fronds, was only collected in the littoral fringe. Although occurring in sheltered localities its open network offers little shelter and this is thought to be the main reason why only four specimens, all female H. albomaculata, were collected from this weed (September 18, 1967). RELATIONSHIP OsTRACODA AND ALGAE 181 Dumontia incrassata (10 grams wet weight) A member of the Rhodophyceae which occurred rarely in pools in the littoral fringe and sublittoral. No live ostracodes were encountered on this weed, presumably because its open network of long thin, tubular fronds do not offer a suitable habitat. Chondrus crispus (25 grams wet weight) Abundant in the eulittoral, this small member of the Rhodophyceae, with short, flat dichotomously branching fronds in an open network, also occurs more rarely in the littoral fringe and sublittoral zone. The samples from the latter zone were barren although three Heterocythereis albomaculata and one H. viridis were recovered on September 18, 1967 from the littoral fringe and a total of 7 species in small numbers from the eulittoral at various dates. Halidrys siliquosa (50 grams wet weight) A medium-sized member of the Phaeophyceae which is frequently but openly branched and rather stiff. This is a common weed of the sublittoral and eulittoral, although it also occurs rarely in deep pools in the littoral fringe. a. From the littoral fringe the following were recovered: H. cellulosa 1 female H. viridis 1 penultimate instar C. lutea 2 females P. ensiforme 1 female L. rhomboidea 1 male, 1 female b. From the eulittoral, all the samples were barren, probably due to the exposed position of the weed. c. The sublittoral collections yielded the following: H. cellulosa 1 female H. albomaculata 2 females P. bradyi 4 females Williams (1969) records much larger numbers of Ostracoda from this weed at his Church Island locality in the Menai Straits. (5,121/100 grams) Pelvetia canaliculata (22 grams wet weight) This weed occurs as tufted bunches of flat fronds on the edge of rock pools in the littoral fringe and eulittoral zone. No live Ostracoda were recovered from it due presumably to its occurrence in exposed situations and its unfavourable morphology. It is interesting to note that of all the algae studied by Colman, (1933, 1940) this was the one with the smallest number of animals and did not yield ostracodes. Porphyra sp. (55 grams wet weight) This red alga with a large single, flat membranous frond, was collected only from the deepest part of a rock pool in the littoral fringe, and only two female L. rhomboidea were collected, both on September 18, 1967. Wieser (1952) failed to recover ostracodes from this species in the Plymouth area. Ectocarpus sp. (15 grams wet weight) This is a common epiphyte on a large number of seaweeds, especially Fucus serratus, throughout the littoral of N. W. Europe. At Monk’s Cave, however, it does not occur in great abundance, and although a small number 182 R. C. WuaTtey anp D. R. WALL of live ostracodes were collected from this alga growing on F. serratus, sur- prisingly none were found where Ectocarpus grows on the rocky substrate in the littoral fringe. This is not explicable in terms of the plant not providing sufficient shelter or suitable attachment area for ostracods because the plant forms a dense network and contains large amounts of sediment. Possibly the factor in the littoral fringe would be dessication because the plant at collection was noted to be very dry and rather brittle. Hagermann (1966, 1969) demonstrated the importance of this plant in providing suitable environments for Ostracoda in areas of dense growths of Fucus. Corallina officionalis (20 grams wet weight) This alga with a hard ‘skeleton’ of calcium carbonate grows densely in shallow pools in the littoral fringe and eulittoral. Although failing to yield a fauna during the winter, at other seasons it yielded 18 and 10 specimens from the littoral fringe and eulittoral respectively. Hagermann (1968) recorded 14 species of ostracods from this plant in Western Norway, the greatest numbers occurring in summer and autumn. Rhodophyceae (80 grams wet weight) A number of species of red algae are here considered together because their form is so similar as to render doubtful accurate identification even to the generic level. Amongst these however, Brogniartella, Gymnogongrus, Ahn- fletia, and Cystoclonium were recognized, all of which are of medium size, branching and with thin fronds which generally display a rather open network. In the deep rock pools of the littoral] fringe and eulittoral zone, ostracodes were collected in moderate numbers, but in the sublittoral, only nine specimens were recovered. Ceramium sp. (18 grams wet weight) Various species of this small red alga with an open network of fine dichotomous fronds occurred in the eulittoral, on rock platforms, and in shallow pools. Samples from the former were barren, whilst one sample from the latter situation, on September 18, 1967, yielded four female H. albomaculata. Laurencia hybrida (23 grams wet weight) This small red alga, with an open network of small delicate branches, occurs on the bottom of pools in the eulittoral zone, and yielded the following: P. variabile 2 females (November 14, 1966) H. villosa P. bradyi 2 females (April 26, 1967) (November 14, 1966) Laurencia pinnatifida (15 grams wet weight) This species with very similar morphology to the above, was collected from eulittoral rock pools but failed to yield Ostracoda. Chaetomorpha sp. (28 grams wet weight) This genus which has a close network of brittle threads, which are un- RELATIONSHIP OsTRACODA AND ALGAE 183 SEASONAL DISTRIBUTION OF LIVE OSTRACODA COLLECTED FROM 35 gms. (€ WET WEIGHT ) OF CLADOPHORA FROM COLLEGE ROCKS, STATION 745 [] C.lutea 200 (TMM x. viridis ye Others S 100 we = a 22 Teil 0 agile TEMPERATURE DISSOLVED OXYGEN CONCENTRATION mi/1. 8 v/ 6 5 Text-figure 1. Seasonal distribution of live Ostracoda collected from 35 grams (wet weight) of Cladophora from College Rocks, Station 745. 184 R. C. WuHaTLey anv D. R. WALL branched, is usually found only in the eulittoral and littoral fringe. At this station it was also encountered in the upper part of the sublittoral, where it yielded only four specimens of H. albomaculata on April 26, 1967 however, two samples collected in the littoral fringe on May 14, 1968, and August 9, 1968 (not shown in Table) yielded 151 and 57 ostracods respectively belonging to C. lutea, H. viridis and H. albomaculata. Furcellaria fastigiata (35 grams wet weight) A red alga with rigid dichotomous branches in an open network and attached by a small holdfast. It was only found in the ‘upper’ sublittoral and whilst the fronds were barren, the holdfasts collected on August 9, 1968, contained 13 adult H. albomaculata and one instar each of H. viridis and P. variabile. Laminaria spp. (75-95 grams wet weight) Two species of the genus, L. hyperborea and L. digitaris, were collected. Because the fronds did not contain ostracodes, and because the form of the holdfasts and their contained fauna were so similar, they are considered together. The ostracodes contained in the holdfasts of the plant from deep pools in the lower part of the eulittoral zone, were the same as those from the ‘upper’ sublittoral. Fifty individuals occurred being dominated by P. bradyi H. albomaculata, H. cellulosa, A. convexa, and L. rhomboidea, which occurred throughout the year, whilst C. /utea was only present during the winter. N. subulata, §. striata, and P. variabile occurred only rarely and irregularly. Station 745 This is at College Rocks, Aberystwyth, Lat. 52°24’55”N, Long 4°05’10”W. and NGR SN 584815. At low tide, immediately to the west of the Old College buildings, a large rock platform, with a distal seawards extension is exposed. From a rock pool in the upper part of the eulittoral zone, algal and sediment samples were collected at intervals between September 1966, and August 1968. The bottom sediment yielded only dead specimens of L. rhomboidea, C. lutea, H. viridis, P. variabile, H. villosa, A. convexa, and H. albomaculata. Of the rock pool algae, Fucus serratus failed to yield live ostracodes; Corallina afficionalis contained a few as did Ulva sp. and Ascophyllum nodo- sum. The largest concentrations of living ostracodes were obtained from tufted growths of Cladophora and Enteromorpha, especially those plants situated near the surface of the pool but overhung by a layer of larger algae, such as Fucus serratus. The same algae, and others situated at the bottom of the pool, yielded significantly lower numbers of Ostracoda, especially during spring collections. This is thought to be the product of small temperature differences; ¢.g. in March, 1967, the bottom of the pool was 9°C. and the top 11°C., whilst the temperatures in August of the same year were 16°C. and 17°C., respectively. The seasonal distribution of living ostracodes from approximately 25 grams (wet weight) of Cladophora sp. taken from all parts of the poo! is given in RELATIONSHIP OsTRACODA AND ALGAE 185 Text-figure 1. The population is generally dominated by H. viridis and C. lutea. During the winter of 1966 and the early months of 1967, the two species were absent but in the April 1967 sample they occurred in abundance, being repre- sented almost exclusively by adults, although a few -1 instars of C. lutea were collected and a number of -1 and -2 instars of H. viridis. The May 1967 sample was similarly dominated by adults of the two species, although H. viridis increased in numbers at the expense of C. /utea. From this spring maximum, the numbers of the two species declined with H. viridis being last recorded in September and C. /utea in November. The next appearance of the two species was in March 1968, one month earlier than in the preceding year. This earlier occurrence can probably be correlated with the fact that the water temperature of the pool in March 1968 was, at 16.5°C., ten degrees higher than in the same month of the preceding year. In 1968, H. wiridis appeared before C. /utea and again consisted principally of adults with only a few -1 instars, and gradually decreased in numbers throughout the summer. C. lutea, however, was represented in March by -4 instars. In April, adults, -1 and -2 instars were collected and the species was represented throughout the summer by adults and -1 instars with very occasional younger moults. The sudden appearance of the two species in the spring may perhaps be related to temperature, especially if the species had wintered in the pool as eggs. In 1967, there was a gap in the sampling interval between the 3rd of March and the 6th of April, and it is perhaps feasible that the eggs could have hatched and the species reached maturity during this period of time. In 1968, in order to investigate this possibility, the sampling interval between January and April was reduced to two weeks. This revealed earlier instars of C. lutea but not of H. viridis and additional samples from Clado- phora in surrounding pools, taken at the same time, exhibited the same population structure. It would appear that either the ontogenetic development to the adult stage can take place within two weeks or, more probably, that the adults and the -1 instars are able to migrate into the pool from nearby, possibly sublittoral population. There is some direct evidence to support the latter suggestion, in that the adults of C. lutea were commonly encountered during the winter in holdfasts of Laminaria, and H. viridis has also been found associated with other sublittoral weeds. This problem of migration is discussed below. On March 27, 1968, a large collection of weeds was made at this station, all from the upper part of the eulittoral, the results of which are given below: Cladophora rupestris (35 grams wet weight) H. viridis 207 adults, 8 instars C. lutea 11 instars H. albomaculata 4 adults, 26 instars H. cellulosa 2 adults L. rhomboidea 1 instar S. striata 3 adults Halidrys siliguosa (210 grams wet weight) H. viridis 9 adults C. lutea 7 instars H. villosa 2 adults H. albomaculata 1 adult R. C. WuaTLey anp D. R. WALL 186 THE RELATIONSHIP OF LIVE OSTRACODA TO ALGAE AT STATION 736 NOIL037109 4O 3iva EULITTORAL SUBLITTORAL LITTORAL FRINGE HT ‘ds evweulwe sndsii9 snapuoys pa 2hydopoyy i snjeiies snon4y | eye6)y8e) eleljoouny — esonbilis SAspileH ‘ds eydiowojeey5 ‘ds eleujwey eplpAy efoueine SIJBURIDIj;O BUl||B105 ‘ds Wnjwesed sndslu9 snipuoy5 $ue96e/6}u e1uoYdishjog al | | eyeiyye19 eydsowoseug $j4ysedni Bi0ydopelD ; ss Smyesses snon4y 9 eadAydopoyy SiBueld{jjO CUl|/B10D “ds sndse90}93 ‘ds euAydiog (= Se! Byejnojjeued B1}9Aleq ie ia CTT TT Be ie HE jaccnane esonbi iis SAupie sndsjio snipuoyD e}Jessesoul e}}uOwNg Sue2seiBju e}Uoy diskjog BWO}OYDIP e\0A}DI0 Byesyjejo eydiowosajug “ds eain snyelies snony saloadS 1V91V OSTRACOD SPECIES tee H. cellulosa H. albomaculata f | | is | H. viridis C.lutea A.convexa Ht tat +++ ty H- ster TH ty pp ay te in| OI le) | | lel +ott a ELS Better ttt FE + tS | ti a tf Hy eeu ae + H. villosa P.flexuosum L. rhomboidea H.tamarindus C.antiquata P.ensiforme P. variabile N. subulata P. normani S. striata L.tenera S.sella C.badia Table 1. The relationship of live Ostracoda to algae at station 736. *Authors now reassign H. tamarindus to Loxoconcha (see p. 177). RELATIONSHIP OsTRACODA AND ALGAE 187 Rhodophyceae (65 grams wet weight) H. viridis 42 adults C. lutea 32 adults H. albomaculata 2 adults H. cellulosa 1 adult P. bradyi 1 adult P. variabile 1 adult, 5 instars Ulva sp. (44 grams wet weight) H. viridis 2 adults C’. lutea 5 instars P. variabile 1 adult, 1 instar H. albomaculata 2 instars The number of Ostracoda recovered from these samples was higher than those of the March sample at station 736. The two stations are environmentally very similar except that 745 is close to the joint mouth of the Rheidol and Ystwyth Rivers and hence has a slightly lower mean salinity (30-330/00) than station 736 (34-350/o0). The relationship between species of plant and ostracode numbers was very similar to that recorded at station 736. Densely intergrown algae, such as Cladophora contained large numbers, whilst those with an open network, such as Halidrys siliqguosa contained many fewer. This is further emphasised by the fact that Fucus serratus (50 grams wet weight), Ascophyllum nodosum (170 grams), Dilsea carnosa (132 grams) and other algae, such as Chorda filum, were collected from the same pool on the same date but were all bar- ren. At the seaward extremity of College Rocks, a rock ledge extends obliquely out to sea. Holdfasts of Laminaria were collected from the ‘upper’ sublittoral, on both the seaward and landward sides of this ledge, with the following results: Landward Side Seaward Side Date Wet weight No. Wet weight No weed (grams) Ostracoda weed (grams) Ostracoda Dec. 6, ’66 70 21 80 0 March 3, ’67 52 36 61 17 June 7, 68 86 46 42 10 Aug. 27, 768 27 27 80 1 The consistently higher number of ostracodes recorded from the landward side is attributed to the holdfasts there being more sheltered from the waves. A further example of the importance of this factor is provided by the fol- lowing data: On March 2, 1968 two approximately equal weight samples (35 grams), of C. rupestris were collected from the eulittoral. The first sample was from immediately below an ‘overhang’ in a rock pool where the plant occurred beneath a dense mat of Ascophyllum nodosum. The second was collected near the surface of the same pool without a protective covering. The first sample yielded 256 live ostracodes, and the second only 22. Station 933 (Lat. 52°13’33” N., Long. 4°27’ W.) At this station, situated between New Quay and the Teify Estuary, a nearly vertical cliff face extends down to a depth of 2 fathoms below OD, 188 R. C. WuaT Ley ann D. R. WALL and the vertical zonation of the littoral as expressed by algae, is extremely compressed. Several collections were made at this station, the results of which are quoted below: Mixture of Ulva and Cladophora (45 grams wet weight) from the littoral fringe: H. villosa 1 adult L. rhomboidea 1 adult H. viridis 1 adult C. lutea 1 instar H. albomaculata 1 instar P. variabile 1 adult, 4 instars Laminaria Holdfast (25 grams) from the lower part of the eulittoral zone. H. viridis 1 adult C. lutea 1 instar H. albomaculata 2 adults H. villosa 1 instar Laminaria (2 holdfasts total 58 grams) from the sublittoral. A. convexa 4 adults H. albomaculata 1 adult, 1 instar C. lutea 1 instar H. viridis 1 adult S.2 concentrica 2 adults Although the number of Ostracoda was very small, it is interesting that in this extremely exposed part of the coast the algae should provide sufficient protection for ostracodes to survive. Ostracoda collected from algae in the ‘lower’ sublittoral zone Between 1962 and 1964, a number of algal samples were collected by dredging from the sublittoral along the coast of Cardiganshire, The algae were unfortunately not identified nor weighed. The Ostracoda recorded from them are given below: Station 556 (52°14'61” N., 04°18'53” W.) Depth 23 feet, June 24, 1968, off the town of Aberarth, large boulders with weeds and many live Foraminifera. L. rhomboidea 7 females L. tamarindus 10 female, 1 male H. villosa 2 female, 12 juv. FH. cellulosa 9 female, 4 male, 5 juv. P. bradyi 2 female M. fulva 2 female L. tenera 1 female P. normani 2 male P. ensiforme 1 female S.2 concentrica 2? juv. Station 647 (52°16’36” N., 04°12’37” W.) Depth 21 feet, September 28, 1964, Cadwag Reef off Llanrhystyd. L. rhomboidea 8 female, 5 male UH. villosa 3 female, 2 juv. H. cellulosa 4 female P. bradyi 3 females Station 105 (52°39'48” N., 04°7'55” W.) Depth 21 feet, April 4, 1962. L. rhomboidea 56 female, 20 male A. convexa 3 female H. villosa 6 female, 1 male, 1 juv. H. albomaculata 2 females, 6 juv. H. cellulosa 1 female H. viridis 7 juv. P. ensiforme 2 female, 1 juv. RELATIONSHIP OsTRACODA AND ALGAE 189 Station 106 (52°27'17” N., 04°07’32” W.) Depth 30 feet, April 12, 1962. L. rhomboidea 29 female, 16 male A. convexa 1 female, 2 juv. H. albomaculata 1 female, 2 juv. P. ensiforme 1 female H. villosa 1 juv. Station 107 (52°75'44” N., 04°40'00” W.) Depth 40 feet, April 12, 1962. L. rhomboidea 29 female, 16 male H. villosa 1 female, 2 juv. H. albomaculata 2 female, 9 juv. 4H. cellulosa 2 female, 2 male A. convexa 1 female H. viridis 1 juv. P. variabile 1 juv. Station 108 (52°26'40” N., 04°19’45” W.) Depth 52 feet, April 12, 1962. L. rhomboidea 9 female, 4 male A. convexa 3 female H. albomaculata 1 female, 1 juv. H. villosa 1 male Station 109 (52°25’45” N., 04°40’20” W.) Depth 45 feet, April 12, 1962. L. rhomboidea 13 female, 10 male, 2juv. H. albomaculata 2 female, 1 male A. convexa 1 female, 1 juv. H. villosa 1 female, 1 juv. Station 110 (52°26'25” N., 04°35’ W.) Depth 22 feet, Avril 12, 1962. H. albomaculata 1 female Station 111 (52°30'31” N., 04°59’42” W.) Depth 40 feet, April 12, 1962. L. rhomboidea 5 female, 1 male After studying these samples, collected before either of the authors worked at Aberystwyth, it became evident that, because sublittoral sediment samples contained few or no ostracodes, further weed samples from this zone would be required. Accordingly, in 1968, further samples were collected by SCUBA divers. The results from which are given below: Station 931 (52°14'15” N., 04°17'48” W.) Depth 16-20 feet, April 28, 1968. Between Aberayron and New Quay. Halidrys siliquosa (with epiphytes, 28 grams wet weight) P. variabile 1 juv. P. normani 9 juv. P. abbreviatum 1 juy. S. contortus 1 juv. Laminaria sp. (holdfast, 50 grams wet weight) A. convexa 1 female Station 932 (52°14’20” N., 04°17’ W.) Depth 15 feet, April 28, 1968. Between Aberayron and New Quay. Rhodophyceae (20 grams wet weight) L. rhomboidea 1 female, 2 male LL. tamarindus 2 juv. S.2 concentrica 1 ? juv. P. variabile 1 juv. P. bradyi 1 juv. H. villosa 1 male A. convexa 1 female 190 R. C. WuaTLey anv D. R. WALL Chondrus crispus (35 grams wet weight) P. normani 7 juv. P. variabile 7 juv. A. convexa 1 female L. rhomboidea 1 female Laminaria sp. (holdfast, 21 grams wet weight) P. variabile 2 female Station 939 (52°24'54” N., 04°14’30” W.) Depth 30 feet, June 16, 1968. Sarn Wallog, off Clarach. Spermothamnium thurneri (130 grams wet weight) H. albomaculata 30 juv. P. variabile 2 female, 4 male, 5 juv. P. abbreviatum 5 female, 1 male, 1 juv. H. viridis 5 juv. S.2 concentrica 1 juv. H. cellulosa 1 female, 1 male Rhodomela conferoides (14 grams wet weight) H. albomaculata 7 juv. L. rhomboidea 2 juv. S.2 concentrica 1 ? juv. H. viridis 4 juv. P. flexuosum 1 male Furcellaria fastigiata (130 grams wet weight) H. albomaculata 2 female, 1 male, 22 juv. P. variabile 1 female, 2 male, 3 juv. H. cellulosa 7 female, 6 male H. viridis 8 juv. P. hibernicum 7 juv. S.2 concentrica 1 ? juv. Chorda filum (120 grams wet weight) H. albomaculata 15 juv. P. variabile 11 juv. P. abbreviatum 1 female, 2 male, 1 juv. H. viridis 5 juv. H. cellulosa 1 male L. rhomboidea 2 juv. S. striata 1 female Station 940 (52°25’10” N., 04°14’12” W.) Depth 20 feet, June 16, 1968. Chondrus crispus (190 grams wet weight) P. variabile 1 female, 4 male, 11 juv. H. albomaculata 16 juv. H. cellulosa 5 female, 1 male H. viridis 9 juv. P. abbreviatum 6 female, 4 juv. P. flexuosum 1 male L. rhomboidea 1 juv. Chorda filum (380 grams wet weight) P. variabile 17 females, 17 male, 32 juv. P. abbreviatum 45 female, 11 male P. subelliptica 2 female, 35 juv. H. viridis 3 juv., 74 juv. S.2 concentrica 5 ? juv. H. albomaculata 1 female, 65 juv. H. cellulosa 4 female, 2 male Ceramium arborescens and Brogniartella byssoides (intergrown and not pos- sible to separate, 260 grams wet weight) H. albomaculata 24 female, 4 male, 22 juv. P. variabile 26 female, 11 male, P. abbreviatum 24 female, 4 male, 22 juv. 46 juv. H. cellulosa 8 female, 5 male P. hibernicum 21 juv. S.2 concentrica 2 ? juv. H. viridis 8 juv. RELATIONSHIP OsTRACODA AND ALGAE 191 Three major factors emerge from these figures: 1. The large number of ostracodes on the ‘lower’ sublittoral algae relative to the much smaller numbers encountered in littoral and ‘upper’ sublittoral phytal environments. 2. The difference in the composition of the ostracode faunas of the ‘lower’ sublittoral algae and that of those of the intertidal and ‘upper’ sublittoral zones. The former contains, for example, P. abbreviatum, P. subelliptica, and S. 2 concentrica, which are not recorded from the latter. The Paradoxosto- matinae are also much better represented and more dominant in the former. 3. The sublittoral algae, whatever their morphology, contain a relatively large ostracode fauna. For example, the “‘boot-lace alga”, Chorda filum, yielded 314 individuals at the “lower” sublittoral station 940 whereas the same weed at station 745, from the eulittoral, was barren. Similarly, the open branched red algae, Brogniartella byssoides and Ceramium arborescens, yielded 274 ostracodes and the open network of Chondus crispus 68. In the intertidal zones, such algae rarely, if ever contain ostracodes. These results seem to indicate that the shelter and protection provided by the algae, whilst being a major controlling factor in the higher zones of turbulence and dessication, is of lesser importance in the lower energy “lower” sublittoral environments. MIGRATION OF OSTRACODA The possibility that ostracodes may migrate seasonally was first suggested by Colman (1940). From samples of Ascophyllum nodosum he recovered a varying number of Ostracoda in a traverse across the littoral. At the landward end of his traverse, he obtained maximum numbers in the summer and minimum in the winter whilst, at the seaward end the reverse was true. He did not, unfortunately, identify the species concerned although Lowndes (in Colman, 1940) stated that some at least were Xestoleberis aurantia nor did he discuss the population age structure. Tressler and Smith (1948) found on te basis of monthly samples taken from the North East Coast of the United States, that in the spring, large numbers of adult L. rhomboidea appeared without the previous occurrence of instars. During September, large numbers of late stage instars were observed but which had, by December disappeared. These authors noted the similarity of their results to those given by Elofson (1941) on the same species and concluded (p. 41) “The most reasonable explanation is that migration of the late larval stages or young adults takes place and is followed by a wintering over in deeper waters where more even temperatures prevail. This would also explain the sudden appearence of adults in the spring without the ap- pearence of larvae”. The most detailed evidence so far presented to demonstrate migration in littoral and sublittoral Ostracoda is that presented by Hagermann (1966, 1969). In the second paper, he demonstrated by field observations and experiment 192 R. C. WHaTLeEy anv D. R. WALL that the degree and rate of migration of cytheracean ostracods is much greater than hitherto thought. This work to a large extent also explains and accounts for the discrepancies between the ontogenetic development and seasonal geo- graphical distribution observed by many authors. The repopulation, in a very short time, of areas in which the faunas had been wiped out by natural disasters, and the rapid rate with which areas from whence Ostracoda had been removed artificially were repopulated, is eloquent evidence of the ability of these animals to migrate. Whatley and Wall (1969:293) also invoked seasonal migration to account for seasonal population age structure anomalies in littoral populations. Similar anomalies in the seasonal distribution at Monk’s Cave (Station 736) may also be partly explained by migration. In the spring, there is a sub- stantial increase in the number of ostracodes inhabiting Cladophora, Entero- morpha, and Ulva in the littoral. This spring increase has been documented by all the above mentioned authors and also by Kornicker (1964). All correlate this increase in numbers with increase in temperature and have also noted the absence of early instars. H. albomaculata, H. viridis, and C. lutea all increase in number in the spring, principally represented as -1 and -2 instars and all being without earlier instars. In the spring sample of the same weed H. viridis and C. Jutea are absent. This seasonal occurrence is unusual and con- trasts with the data of Elofson and of Hagermann, especially with respect to H. viridis. The latter author (1966, p. 15) stated: “The reproductive period of H. viridis started in late May to early June when the first larvae of stages 1-4 were found. In August no adults were found but only larvae of stages 5-7. They then entered the 8th in the autumn and became adults in the following April or May. Thus, this ostracode is annual and dies immediately after re- production in June”. Our results differ in the absence of early instars in the spring and in the absence of H. viridis and C. lutea in the littoral zone during the winter. Both these phenomena may be explained by migration in that C. lutea appears to overwinter as adults in Laminaria holdfasts in the sublittoral. This species was almost always present in holdfasts in the winter, whilst with rare excep- tions, it was not encountered in the same microenvironments during the sum- mer. During the winter, H. viridis was encountered live from only one sample in the intertidal zones, although relatively large populations occurred throughout the year in the “lower” sublittoral. Of these latter, the winter collec- tions revealed penultimate instars and adults (stations 105-111) and those of the summer, mainly early instars (stations 931-932-939-940). This evidence, to- gether with that quoted above for station 745, would tend to suggest a systematic seasonal migration of H. viridis into the “lower” sublittoral zone for the winter and a return to the intertidal zone in the spring. The same may also be postulated for C. /utea, with migration between the intertidal area and the upper sublittoral zone, and also probably for H. albomaculata. The only other feasible explanation for the observed facts, is that ontogenetic development could take place in less than the period of the sampling interval. Whilst this could perhaps be possible in the case of station 736, where only three spring RELATIONSHIP OsTRACODA AND ALGAE 193 collections were made, it is exceedingly unlikely at station 745, where samples were taken monthly for two years and at two week intervals during the spring in 1968. In any case the evidence put forward by Hagermann (1969) that H. viridis is an annual species would effectively argue against any such possi- bility. With the exception of the Chlorophyceae, algae yielded few ostracodes in the intertidal zone, and these almost always occurred as adults. Of the 160 specimens collected from other than green algae at station 736 only 11 occurred in the winter sample (November 14, 1966), 57 in the two autumn collections (September 18, 1967) and (August 9, 1968), and 92 in the three spring/early summer collections (April 24, 1967; March 2, 1968; May 14, 1968). The low number of individuals, and the overwhelming preponderance of adults, is probably a reflection of the fact that they do not provide suitable environments for ontogenetic development. Some of the species encountered appeared to be “accidental” in that they occurred outside their normal ecological niches. C. antiquata, N. subulata, and L. tenera are more usually encountered in associa- tion with inner shelf sediments. P. ensiforme is more properly a phytal species of the sublittoral and other species derived by passive or active migration from large sublittoral populations are P. bradyi and A. convexa. Both these species inhabit Laminaria holdfasts in the winter, but in the other seasons may be found on other adjacent sublittoral weeds and, more rarely, also in the eulit- toral. The distribution of H. viridis is essentially similar. The intertidal and “upper” sublittoral weed yielded four L. rhomboidea in the winter sample, 21 in the three spring and 28 in the two summer samples, being almost exclusively adults. It is tempting to suggest that these adult L. rhomboidea were derived by migration from the large sublittoral population of this species. In the “lower” sublittoral, the ostracode populations consist of both adults and instars and stations 939 and 940 yielded virtually complete age group populations, with, for example, —7 to adult in H. albomaculata, and -6 to adult in P. abbreviatum, P. variabile, and H. viridis. This population age structure is evidence of ontogenetic development taking place in situ. Unfortunately, due to inclement weather and to many other problems inherent in sampling the sublittoral, detailed and regular seasonal sampling was not possible in the ‘lower’ sublittoral and the exact nature of its fauna as a source of supply by migration to the higher littoral zones can only be surmised. The overwhelming conclusion is, however, that such species as referred to above do exhibit regular seasonal migrations between the sublittoral and the higher intertidal littoral zones. It is not implied that the total populations of such species as H. viridis, C. lutea, and H. albomaculata undertake this migration nor that it is necessary to the life cycle of the species. We have abundant evidence that a large, if not the largest percentage of the population complete their life cycle within the sublittoral. The fact that a large proportion of these populations does migrate seems to us irrefutable. 194 R. C. WHATLEY AND D. R. WALL FACTORS GOVERNING THE NATURE OF THE RELATIONSHIP BETWEEN OSTRACODA AND ALGAE Several factors are thought to be fundamental to the observed dependence of Ostracoda on algae in high energy environments. These are listed below, not necessarily in order of importance, and although they are treated separately, the authors realise that they are all to varying degrees interrelated and interdependent. 1. The morphology of the plant.— The form of the alga has been empha- sized as a controlling factor in the density of its epifauna by such workers as Colman (1940), Wieser (1952), Reys (1963), and Hagermann (1966, 1969). Tufted algae, such as Cladophora with a close dense network, contain the largest number of ostracodes by providing a high degree of protection against turbulence and dessication. On the contrary, algae with an open network of branches or flat fronds, such as Dictyota dichotoma and Pelvetia canaliculata contain few or no Ostracoda. This relationship is very apparent in the eulittoral and “upper” sublittoral zones, and even in the littoral fringe, where wave action is only active at high Spring Tides, the effect of the form of the algae is very noticeable. Along the Cardiganshire coast, in the “upper” sublittoral, the only effective protection is provided by the holdfasts of Laminaria and Furcellaria, the fronds of these plants, other algae and the sediments being barren of living ostracodes. A similar situation exists along the exposed parts of the southern coasts of Argentina and Chile where, in the “upper” sublittoral, Ostracoda are virtually restricted to the holdfasts of Macrocystis which are, apart from being much larger, very similar in their morphology to those of Laminaria, 2. The seasonal development and degree of epiphytation of the algae.— Hagermann (1966, 1969) discussed the importance of both of these factors with regard to the provision of suitable substrate for ostracodes. Generally speaking, the greater the density of epiphytes, the greater the density of the ostracode epifauna. Also, the more mature the plant, the better environment it provides, with the exception of certain times when such plants as Fucus serra- tus are, during their reproductive period, covered with a slimy secretion which seems to inhibit ostracodes. Those plants with luxurious summer and little winter growth must be expected to contain quite different epifaunas, at least in terms of density at these seasonal extremes. The present authors have noticed that many algal species, such as Cladophora rupestris and Enteromorpha clathrata “die back”, become white, and also lose their dense network of branches during the winter months. This close network is replaced by a much more open mesh of “woody” branches which appears much less favoured by the ostracodes. This factor may be equally responsible, together with falling temperatures, for the migration of certain species out of the eulittoral into the sublittoral for the winter. RELATIONSHIP OsTRACODA AND ALGAE 195 3. The overall situation of the algae within the intertidal and sublittoral zones. —Colman (1933) and Evans (1947) used the term “critical level” in attempting to isolate and define those levels, particularly in the intertidal area, which are most critical in relation to the vertical distribution of plants and animals. Wieser (1952), who prefers the term “critical zones’, stated that the microfauna will be greatly influenced by the vertical distribution of that of algae which support an epifauna. Evans recognised five critical levels within the eulittoral zone and Wieser recognised three critical zones, two within the eulittoral and the other at the eulittoral/littoral fringe boundary. The present authors are able to recognise in the area studied, a critical level at the boundary of what we call the “upper” and “lower” sublittoral on the basis of the distribution of the Ostracoda. Although many species are common to the two parts of the sublittoral, others, such as P. abbreviatum, P. subelliptica and S. ? concentrica, occur in the “lower” sublittoral but are absent in the higher zones. Equally, such species as P. bradyi and C. lutea are common in the higher zones but absent in the “lower” sublittoral. This critica] level seems to mark the lower limit of certain intertidal forms and the upper limit of certain “lower” sublittoral forms. Above this level, the morphology of the plant exerts a marked influence on the density of its epifauna, whilst below it this factor is much less operative. This would appear to indicate that the critical level is determined by one major observable factor, that of turbulence. The only physical factor which we know to radically change at this level is that of surf action, in that wave base of breaking waves is, at low tide, at about the two fathoms mark, depending of course of the strength and direction of the wind. In the “lower” sublittoral, surf action is only operative during the coincidence of extreme low tide and extreme storm and this could well explain the negligible effect that the form of the alga has on the density of its ostracode epifauna in this zone. Above this level however, surf action is effec- tive and ostracodes inhabit only those algae which afford the greatest degree of shelter and protection. The exact depth below OD. at which this level occurs cannot be determined with accuracy. Perhaps it should be more properly referred to as a critical zone, the position of which varies conditionally upon the configuration of the sea bed and the direction and strength of the prevailing winds. The position of this zone may even vary seasonally since, for example on the Cardiganshire coast, storms are more common in the winter months than in the summer. On exposed coasts, this zone will be at a lower level than on more sheltered ones whilst in very sheltered areas with little tidal range, it may well not be recognisable. If the lower level of surf action delimits a critical zone or level, it is not unreasonable to suppose that the upper limit may do the same. This to a certain extent seems to be true. Surf action affects the eulittoral and “upper” sublittoral zones during a large part of the tidal cycle, whereas the littoral fringe is only notably affected during high Spring Tides and storms. Entero- morpha and Cladophora from the eulittoral zone at station 736 yielded only occasional ostracods in the eulittoral, whereas the same weed at the same station produced some 800 from the littoral fringe. The decreasing effect of 196 R. C. WuHaT Ley anp D. R. WALL surf action at the eulittoral zone/littoral fringe boundary is marked by a change in the population density rather than in the specific composition of the fauna. Species such as H. albomaculata, A. convexa, and H. villosa occur in all parts of the intertidal and sublittoral zones and are evidently able to with- stand surf action and also the various physico/chemico vissiscitudes which cor- respond to the intertidal environments, such as diurnal changes in temperature, salinity, pH, O» concentration, dessication, and turbulence. Other species, such as P. abbreviatum and P. subelliptica may be restricted from entering the higher littoral zones by any one or more of these factors. 4. The micro-situation of the algae-—It has been shown that at station 745, Laminaria holdfasts and Cladophora, collected from the same zone and pool respectively, contained many more ostracodes if the plant were situated in a sheltered position than if it were from a more exposed site. Although we have no further evidence, this is thought to be a general rule and is supported by Hagermann’s (1968) work in which he emphasised the fact that Corallina officionalis contains a very rich epifauna when it is covered by various red and brown algae. 5. The relationship to food supply.— The nature of the food supply of small animals such as Ostracoda, especially in the sea, is always difficult to determine. The genus Paradoxostoma has a styliform mandible which is generally accepted as an adaptation for obtaining nutriment in the form of plant ‘juices’. The virtual restriction of the genus to phytobenthic enviroments is evidence of an undoubted relationship with algae. However, since the genus has not, to the knowledge or ourselves, been seen “sucking” plants and since it can also be found, albeit rarely, in non phytal environments, its direct rela- tionship upon plants for nourishment must be considered conjectural. Brady (1868:457) states: “Although it appears to me more fully conformable with what we know of the general habits of the Crustacea and more fully ex- planatory of the peculiarities of the Paradoxostomatinae if we suppose their diet to consist of microscopic animalicula rather than the juices of algae or of animals much higher in organization than themselves’. It seems impossible to us that the specimens of Paradoxostoma frequently encountered in Corallina or in old and “woody” holdfasts of Laminaria, could possess such a relationship with the host of direct nourishment. We feel it is much more probable that, without ruling out the possibility that certain members of the genus may have a direct food source relationship with the host alga, that the principal food of this genus is diatoms, bacteria etc. which are themselves associated with the algae. Many other well-known phytal species, such as H. viridis, C. lutea and H. albomaculata, do not have specialised mouth parts and neither do such species as L. rhomboidea, H. viridis, A. convexa, and H. cellulosa which are found in a variety of other habitats as well as the phytal. This is ample evi- dence that to live in association with algae, it is not necessary for the ostracode to obtain its food directly from the plant. RELATIONSHIP OsTRACODA AND ALGAE 197 Elofson (1941), considered that microscopic algae, associated with the larger plants, were the major food source and quoted as evidence the frequent occurrence of diatoms in the gut of ostracodes, a view supported by Hagermann (1966). Dr. R. Williams (verbal communication) suggests that proteinaceous antibiotic sustances secreted by certain algae, presumably to prevent the at- tachment of epiphytes, may provide an important food source for their asso- ciated epifauna. Both authors have independently observed C. lutea and H. albomaculata apparently “grazing” or “browsing” on Cladophora rupestris and Ulva intestinalis. R. C. Whatley has also seen Loxoconcha elliptica (Brady, 1868), prescribing an advancing spiral browsing action on the branches of Enteromorpha, and Parakrithella hanaii, a common phytal species from the Argentine littoral, apparently doing the same on Enteromorpha, Cladophora, and Ceramium. In all of these cases the authors have not been able to observe on what the animals were feeding. However, we are of the opinion that small diatoms and bacteria are the most obvious possibility. With the possible exception of the Paradoxostomatinae, algae do not seem to serve as a primary food source for ostracodes. There does not seem to be any evidence that the epifauna favour any particular weed, therefore this cannot be invoked as a possible factor in explaining the observed preference of cer- tain plants by ostracodes over others. 6. The sediment content of the plant.— Dahl (1948) noted an increase in the density of the microfauna on algae related to an increase in the amount of contained detritus. Wieser (1959) found that the number of nematodes in- creased with increase in the amount of sediment, whilst the number of creep- ing and clinging animals decreased. Hagermann (1966, 1969) also noted this effect, and in the former paper pointed out that the amount of sediment con- tained within the plant is to a large extent a function of the degree of turbu- lence. The present authors have also noted this reiationship which they regard as further evidence of the supreme importance of turbulence in affecting the distribution of animal life, in the sense of a fundamental factor, within the littoral zones. An analysis was made of the sediment content in the previously described collection of Laminaria holdfasts, from a sheltered and from an ex- posed situation at station 745: (weights in grams) Sheltered Exposed Weight of Weight of No. of Weight of Weight of No. of Date Laminaria Sediment Ostracoda Laminaria Sediment Ostracoda Dec. 6, ’66 70 22 21 80 15 0 VED oe 52 18 36 61 8 17 June 7, ’68 86 19 46 42 6 10 Aug. 27, ’68 47 7 27 80 15 1 Those holdfasts from the sheltered station contain more sediment and more ostracodes that those from the exposed site. From this it might be sug- gested that an increase in sediment is accompanied by an increase in Ostracoda. 198 R. C. WHATLEY AnD D. R. WALL However, if the results from the exposed site are considered alone, the reverse is true. The results from the sheltered site considered alone, seem to indicate little relationship between population density and amount of sediment. It might even be said in respect of the latter, that the number of ostracodes increase in spite of the increase in sediment, not because of it. The authors have noticed that whilst strictly phytal Ostracoda are not greatly influenced by the amount of sediment in the algae other species, which are more commonly found in sedimentary environments, are normally only found in association with those weeds which contain large amounts of sedi- ment. One of the authors (R. C. Whatley) is currently engaged in studying the Ostracoda inhabiting the holdfast of Macrocystis from the southern coasts of Argentina and Chile. Here, although the data are as yet incomplete, there seems to be a notable relationship between the density and specific composition of the ostracode fauna and the particle size of the entrapped sediment. In the more exposed areas, the sediment is usually of large size, often in the form of shell fragments. In these cases the density of ostracodes is very low, whereas in more sheltered environments, such as within the Ria at Puerto Deseado, Province of Santa Cruz, the sediment is of mud and silt, and the holdfasts contain many more species and individuals. Very few species are common to the two. We realise that there are many other important factors capable of in- fluencing this relationship between the plant and its epifauna, such as the role of the plant in preventing dessication, in providing oxygen, and in providing protection from extreme temperature change, and probably as many others, which we are unable to consider here. We believe, however, that the major factors are those six which we have considered above. A COMPARISON OF THE PRESENT RESULTS WITH THOSE OF PREVIOUS WORKERS Colman (1940) counted the numbers of Ostracoda per algal sample from the littoral of Church Reef, Wembury. He did not identify the species but stated (p. 143): “Recently (April, 1939) I collected some from Church Reef which Mr. A. G. Lowndes was kind enough to examine; he found that they were all Xestoleberis aurantia (Baird). They were not abundant, however, and dur- ing the summer there is certainly more than one species present”. Since X. aurantia has not been found along the Cardiganshire coast (and this in itself is a problem of some interest since it is one of the most common phytal species in British waters), it is only possible to compare the results from the two areas in terms of numbers per 100 grams of wet algae. RELATIONSHIP OsTRACODA AND ALGAE 199 Colman (1940) Present Study Pelvetia canaliculata 0 0 Fucus spiralis 0.5 0 Lichina pygmaea 0 - Fucus vesiculosus 0 - Ascophyllum nodosum & Polysiphonis lanosa 353.3 0 Fucus serratus 3.0 157 Gigartina stellata 0.5 - Laminaria digitata (holdfasts) 7.5 33.5 The number of ostracodes from both areas is small, probably due to the fact that they are exposed coasts. With the single exception of Laminaria, the Welsh algae contained less Ostracoda. At all our stations, Ascophyllum nodo- sum was barren of ostracodes, whereas a dense population was found on this weed at Wembury. This may be possibly due to some special selection on the part of X. aurantia, although this is not evident in the work of other authors. Williams (1969), however, recorded more of this species on Ascophyllum no- dosum at his Port Castell locality than on other weeds. This latter author also demonstrated that this plant in Anglesea, especially in the Port Castell locality, (339/100 grams), provides a favourable habitat for ostracodes. The absence of ostracodes on this weed in our area of study may perhaps be due to the fact that this coast is exposed to frequent storms from the west and southwest. Wieser (1952) studied the fauna occurring on weeds in front of the Marine Biological Station at Plymouth. He divided the algae here into “leaf- like” forms, such as Porphyra laciniata, and Nitophyllum punctatum, and “tufted” forms such as Ceramium sp., Cladophora rupestris, and Lomentaria articulata, each of which type contained its own particular fauna. This author collected ostracodes on a transect from MHW to MLW but was unable to find any relationship between density and tide level. The numbers ranged between 7 and 280 per 1 gram dry weight of weed. He stated (p. 150) “In my opinion the most important factor is the silt content”. As in the present study, Porphyra, which was encountered in the littoral fringe only, did not contain ostracods. Nitophyllum, with similar “leaf’-like form, contained between 34 and 60 specimens per 100 grams and was collected at 0.7, 1.20 and 3.0 metres below Chart Datum. The fact that ostracodes are able to inhabit “leaf”-like algae in the “upper” sublittoral zone at Plymouth is probably due to the protection afforded by the extensive breakwaters and Drakes Island from the full force of the waves. The higher numbers of Ostracoda collected from the eulittoral weeds by Wieser, may also be attributed to the same factor. Hagermann (1966) studied the total fauna of Fucus vesiculosus and asso- ciated epiphytes in the @resund. He reported 6,000 ostracodes in summer and 2,000 in winter from 200 grams wet weight of this weed. The dominant species were H. viridis, S. nigrescens (Baird), H. cellulosa, X. aurantia, P. abbreviatum, and P. variabile. The distinction between this area and the Cardiganshire coast is considerable in hydrographic terms. The former has a 200 R. C. WuaTLey ann D. R. WALL tidal range of only a few cms and is largely sheltered from major storms, whilst the latter has a maximum range of 7 metres and is open to frequent westerly and southwesterly storms. The same author in his (1968) study of the ostracode epifauna of Corallina officionalis, from a slightly reduced saline environment in western Norway, found many ostracodes, especially in summer and early autumn. The weed was collected as an undergrowth of Fucus and was thus well protected from turbulence and dessication. Four of the species, Elofsonella concinna (Jones), Semicytherura nigrescens (Baird), Xestoleberis depressa (Sars), and Paradoxostoma pulchellum (Sars) were permanent annual inhabi- tats of the weed and reproduced in it. Others, such as Semicytherura incon- spicua (Klie), Xestoleberis pusilla Elofson, were probably accidental, Cythere lutea occurred only as a winter migrant in the adult stage. In summer this species was present in the sublittoral at three metres and this seasonal migra- tion, in the opposite direction to that noted by the present authors, was attributed to the fact that the eulittoral was at a temperature too high to support the species during the summer. A further work by this author (1969) demon- strated that the type of algae and the seasonal development of the plant and epiphytation were very important factors in the distribution of H. viridis in brackish waters of the @resund. The work of Williams (1969), who studied five intertidal localities from Anglesea, contains results which, in general conform with those presented by us. CONCLUSIONS Whilst there are many regional differences, due to hydrographic and climatic factors and also to the faunal and floral provincial differences in the Ostracoda and the algae, whilst in different areas different ostracods inhabit the same weed, or the same ostracodes inhabit different weeds; the factors fundamental to the relationship between the animal and the plant are thought to be those outlined above. These factors have been arrived at from our own studies and from those of other workers. Most of the data we have concerning this relationship is from Europe and to a lesser extent from the United States, and it is important, to test the uni- versality of these factors, to have data from other parts of the world. Very preliminary results from the Argentine suggest that the same factors are operative as in the North Atlantic and adjacent seas. Perhaps the dependence of Ostracoda upon the algae, to provide attachment and protection on this ex- posed and stormy South Atlantic coast, is even more pronounced. Of the 160 species isolated to date in a study of the Argentine continental shelf and littoral, approximately 80% are restricted to the latter where, with the excep- tion of certain muddy tidal lagoons and estuaries, there is an almost 100% dependence upon algae. The form of the plant, its vertical position within the littoral as well as its micro-situation and contained sediment, all seem to be important controlling factors in the selection of the weed by its ostracode epi- fauna. It is also worthy of note that in the eulittoral and sublittoral, sedi- RELATIONSHIP OsTRACODA AND ALGAE 201 mentary environments are, with very rare exceptions, not inhabited by ostra- codes and moreover, the genera which would normally be encountered in these and inner shelf sedimentary environments of Europe, are here found in associa- tion with algae. Many examples could be given. For example, the Leptocytheri- dae (Whatley and Moguilevsky in this publication) are much more phytal in habit here than elsewhere. Also, other genera such as Argilloecia, Paracypris, Macrocypris, and the great majority of the Hemicytheridae, are found com- monly, and often exclusively, on algae together with well-known phytal genera such as Parakrithella, Xestoleberis, and Paradoxostoma, REFERENCES Brady, G. S. 1868. A mongraph of the Recent British Ostracoda, Linn. Soc. London, Trans. 26 (2), pp. 353-495, pls. 23-41. Chapman, G. 1955. Aspects of the fauna and flora of the Azores, VI. The density of animal life in the coralline zone. Ann. Mag. Nat. Hist., 12th ser., 8, pp. 801-805. Colman, J. 1933. The nature of the intertidal zonation of plants and animals. Jour. Mar. Biol. Ass., United Kingdom, 18, pp. 435-476. 1940. On the faunas inhabiting intertidal seaweeds. Jour. Mar. Biol. Ass., United Kingdom, 24, pp. 129-183, 23 tables. Dahl, E. 1948. On the smaller Arthropoda of marine algae, especially in the polyhaline waters off the Swedish west coast. Dissertation, Lund. Undersokn over @resund, vol. 35, pp. 1-193. Elofson, O. 1941. Zur Kenninis der marinen Ostracoden Schwedems mit Besonderer Berucksichtigung des Skageraks. Zool. Bidr. Uppsala, 19, pp. 215- 534. Evans, R. G. 1947. The intertidal ecology of Cardigan Bay. Jour. Ecol., 34, pp. 273- 309, 10 text-figs., 5 tables. Hagermann, L. 1966. The macro- and microfauna associated with Fucus serratus L., with some ecological remark. Ophelia, 3, pp. 1-43. 1968. The Ostracod fauna of Corallina officionalis L. in western Nor- way. Sarsia, 36, pp 49-54. 1969. Environmental factors affecting Hirschmannia viridis (O. F. Miiller) (Ostracoda) in shallow brackish water. Ophelia, 7, pp. 79-99, Kornicker, L. S. 1964. A seasonal study of living Ostracoda in a Texas Bay (Redfish Bay) adjoining the Gulf of Mexico. In Ostracods as ecological and palaecological indicators. Pubbl. staz. Zool. Naples, 33 suppl., pp. 45-60. Lewis, J. R. 1964. The ecology of rocky shores. English Universities Press, London. 323 pp. Ohm, G. 1964. Die Besiedlung der Fucus-Zone der Kieler Bucht und der west- lichen Ostsee unter besonderer Beriicksichtigung der Mikrofauna. Kieler Meeresforsch., 20, pp. 30-64. 202 R. C. WHaTLey anv D. R. WALL Reys, S. ‘ 1963. Ostracods des peuplements algaux de l’etage infralittoral de sub- strat rocheux. Recl. Trav. Stn. mar. Endoume, 28 (43), pp. 33-47. Tressler, W. L., and Smith, E. M. 1948. An ecological study of seasonal distribution of Ostracoda, Solomon Island, Maryland region. Contr. Chesapeake Biol. Lab., 71, pp. 1-57. Whatley, R. C., and Wall, D. R. 1969. A preliminary account of the ecology and distribution of Recent Ostracoda in the southern Irish Sea. In J. W. Neale ed. The taxonomy, morphology and ecology of Recent Ostracoda. Oliver and Boyd, Edinburgh, pp. 268-298. Wieser, W. 1952. Investigations on the microfauna inhabiting seaweeds on rocky coast, IV. Studies on the vertical distribution of the faunas in- habiting seaweeds below the Plymouth Laboratory. Jour. Mar. Biol. Ass. U. K., 31, pp. 145-174. 1959. Zur Okologie der Fauna mariner Algen nit besonderer Beruch- sichtingung des Mittelmeeres. Int. Revue. ges. Hydrobiol., 44, pp. 137-180. Williams, R. 1969. Ecology of the Ostracoda from selected marine intertidal localities on the coast of Anglesea. In J. W. Neale ed. The taxonomy, morphology and ecology of Recent Ostracoda. Olivier and Boyd, Edinburgh, pp. 299-327. R. C. Whatley, D. R. Wall, Divisién Micropaleontologia, Burmah Oil Co. Facultad de Ciencias Naturales of Australia, y Museo, 10 Stirling Highway, Universidad Nacional de la Nedlands, Perth, Plata, W. Australia. Paseo del Bosque, La Plata, Argentina. and Department of Geology, University College of Wales, Aberystwyth, Great Britain. DISCUSSION Dr. R. L. Kaesler: You mention the importance of protection the algae pro- vided in the case of some of the tufted algae. How important is the surface area? I would think that as the surface area increases, there would simply be more room for the ostracodes. Dr. Whatley This is extremely important but how does one go about measuring surface area of algae. Hagermann used a formula in his 1967 paper which we tried at one stage to employ but found to be extremely unsatisfactory. The major problem was always to separate out the epiphytes and in some cases the microepiphytes and the residual organic and inorganic material contained with- in the plant to arrive at some reasonable estimation of its surface area. This, in the very tufted plants with a great deal of epiphytic growth and con- tained sediment, proved difficult if not impossible. As a result of this we abandoned a consideration of surface area in favour of that of wet weight RELATIONSHIP OsTRACODA AND ALGAE 203 of algae. However I am certain that available surface area must exert a con- siderable influence on the density of ostracod occupation of various species of algae and this is a factor which should be given more consideration in future studies. Anonymous: What’s the maximum depth of your sub-littoral zone? Dr. Whatley We consider that the sub-littoral zone in the context in which we have used the term extends out to about 5 fathoms and this depth marks the out- ward limit of our algal collections. Dr. J. W. Neale: I covered this to some extent in the Naples Symposium of 1963 and in littoral environments it seems that surface area is less important than what one might call tuftiness and ability to retain moisture. This comes out very well in the work of Colman (1940) and Wieser (1952). I was particu- larly interested in your mention of die back in the winter coupled with the migration of Ostracoda because Tressler and Smith (1948) found this pheno- menon of migration in their Solomon Island work. They attributed this to change in temperature and suggested that the ostracods sought the more equable temperatures of the deeper waters during the winter. How would you rate the importance of cover as a factor compared with that of changing temperature? Dr. Whatley As we have stated in the paper, we regard the “die back” of algae and the causative fall-off of temperature in late autumn, as being of equal impor- tance in causing a migration of ostracods from the eulittoral to the sub-littoral for the winter. The reverse migration in the spring is also thought to be due equally to renewed algal growth and increased temperature. Hagermann (1968) has recorded that Ostracoda migrate out of the eulit- toral into the sublittoral in western Norway during the summer months and concludes that this migration is to escape extreme high summer temperatures although we have not observed this phenomenon. Dr. Neale: Yes, but is there not the factor of constancy or equability involved as well? Dr. Whatley: It could well be. ‘ / » pa om. =e Niet: hi be ema ay § ant 1 * ¥ jl ndons' ] y 1g alt efies i if ee tit fh ‘€; tiNie nt? a ¥ same, atin tere ea oe nr, _ Ye siptoaqar dc eslgalt. Acad cesta ei = te lt bm m cy Td de! Ty ry » § / : bat so0Ti tte rag hae ee ie. bavon : ; yp bY) eas ) vari hehvapor aad MOO ieel - 7 ; ily) a d isi ? i valond “sG ; 4s 7 vis - iif mah 7 TO THE PROBLEM OF NODING ON CYPRIDEIS TOROSA (JONES, 1850) BERND VESPER Zoologisches Institut und Zoologisches Museum, Hamburg ABSTRACT Among Ostracoda Cyfrideis torosa is the best known example for the development of nodes on their shells. Cypfrideis torosa, which lives in slack waters, was collected by the author in different areas on the coastal region of the North Sea (not directly in the North Sea but in ditches behind the dike) and in slack waters along the shore of the Baltic Sea in Schleswig-Holstein. Smooth as well as noded specimens occur in the sampling area. The results: The salinity of 50/00, which Schafer fixed in 1953 as the upper limit for the occurrence of Cyprideis torosa is by far too low, since the nodes appear in a range of salinity from 1.8 to 14.50/00. The intensity of the nodes differs in the various ranges of salinity. At higher salinity the intensity of the nodes is distinctly weaker than at middle or very low salinity. Moreover the intensity of the nodes is different in the different regions studied, in spite of nearly the same salinity. The nodes may occur differently strong on both valves. As to the number of the nodes, different combinations of nodes may be developed, whereas their location seems to be constant. ZUSAMMENFASSUNG Unter den Ostracoden ist Cyprideis torosa fiir die Ausbildung von Schalen- buckeln wohl das bekannteste Beispiel. Cyprideis torosa, der ja ein Stillwasserbewohner ist, wurde vom Autor in verschiedenen Gebieten im Bereich der Nord- und Ostseektiste Schleswig-Hol- steins gesammelt. In dem Untersuchungsgebiet wurden sowohl glatte als auch gebuckelte Exemplare der oben genannten Art angetroffen. Dabei ergaben sich folgende Resultate: Der Salzgehalt von 50/oo, den Schafer (1953) als obere Grenze fiir das Vorkommen von gebuckelten Exemplaren angibt, ist als erheblich zu niedrig angesetzt, denn gebuckelte Tiere treten in einem Salzgehaltsbereich von 1.8 bis 14.50/00 auf. Die Intensitat der Buckel ist in den einzelnen Salzgehaltsbereichen ver- schieden. Bei héherer Salinitat ist der Ausbildungsgrad der Buckel deutlich geringer als bei mittlerem oder sehr niedrigem Salzgehalt. Ferner ist der Ausbildungsgrad der Buckel trotz annahernd gleichem Salzgehalt in den verschiedenen untersuchten Gebieten unterschiedlich. Die Buckel kénnen auf beiden Schalenhalften unterschiedlich stark ausge- pragt sein. Was die Anzahl der Buckel anbetrifft, konnen verschiedene Buckel-Kom- binationen ausgebildet werden, wobei die Lage der Buckel konstant zu sein scheint. INTRODUCTION Among Ostracoda Cypfrideis torosa (Jones, 1850) is the best known exam- ple for the development of nodes on their shells under certain conditions. According to available data from the literature, generally the shells of individuals of Cyprideis torosa living in low salinity develop a row of nodes, but individuals in higher salinity have a smooth shell. The named species is called “Cyprideis torosa”, the unnoded form should correctly be cited as “Cyprideis torosa forma litoralis”, and the noded form as “Cyfrideis torosa forma forosa”. 206 B. VESPER dug pA PAA Om SS ae (ory Flensburg (ee Zz S = ae, 2 oO aa Schleswig D ° ° A - Kleiner z ee ( 4 Binnensee Kiel SD aa ¥y Friedrichskoog Neufelder KQ0g 0 10 20 30 40km { > Hamburg ze Text-figure 1. Study areas in Schleswig-Holstein. OBSERVATIONS BY THE WRITER I have collected Cyprideis torosa, which lives in slack waters, on the coast of the North Sea and the Baltic Sea in corresponding waters (Text-fig. 1). On the coast of the Baltic Sea, there are numerous lagoons along the shore; in the area of the North Sea there are ditches behind the dike. All localities con- tain brackish water and are in constant or fluctuating spatial continuity with the marine living space. About the noded forms of Cyfrideis torosa a general statement can be made, concerning the distribution of the single nodes on the shells. Sandberg (1964) stated that the total number of nodes known to occur in the genus Cyprideis is seven, but that no species has yet been observed to have exhibited NopInGc oF CyPRIDEIS TOROSA 207 Text-figure 2. Cyprideis torosa, right valve: location and designation of the nodes, (a) usage of Sandberg, 1964, (b) usage herein. all seven. In a general scheme (Text-fig. 2a) he showed the distribution of the nodes on the surface of the valve. I have numbered the nodes differently from those by Sandberg and have done this in succession of their appearance (Text- fig. 2b). It can be stated that in all samples which contained noded forms, if only one node is present it is mostly the node which Sandberg called number two (= my node no. 1). Node number one of my scheme always appears first; in the presence of two nodes, node number three may possibly appear before number two, but this is an exception. As to the distribution of the nodes on the valve surface, different com- binations are possible. In one sample, I could observe variations of completely unnoded to heavily noded specimens. Text-fig. 3 shows some of possible com- binations of nodes on the females in one sample of a sampling area. The same condition exists in the males. A number of general statements were also made by Sandberg (1964): 1. Nodes are nearly always stronger on the right valves. 2. Nodes may be limited to the right valve. 3. No specimen had been observed in which the left valve was noded and the right valve was unnoded. 4. The females commonly are more strongly noded than the males. 5. The right valve seems to be distinctly preferred with regard to noding. 208 B. VESPER left valve right valve in front behina behind in front unnoded oe o> ‘unnoded quite a weak node unnoded but distinctly recognizable unnoded os cee a distinct noae unnodea (a> (Gy) appearing of a second node two well marked. one weak node nodes two nodes, not quite so strong aS on three strong nodes the rignt valve three nodes, not quite so strong aS on three strong nodes the rignt valve tnree strong nodes; oO. IO) three strong nodes; node No. 4: weak © roy o P node No. 4: weak three strong nodes; node No. 7: weak three strong nodes; ove node No. 4: weak ro) Text-figure 3. Combinations of i ure 3. the nodes occurring on the valves of fem of Cyprideis torosa. ‘ ce Nopinc or CypRIDEIS TOROSA 209 oo of ee Oo° 2 a b c d e Text-figure 4. Peculiarity in the forming of the nodes. In general the nodes have a round extension. Divergences as can be seen in Text-fig. 4 are possible. Node number three and number two may respectively show an upward and backward hooklike extension, or node number one is long and not round as it is common. Other than node number one, there may appear two small nodes which are distinctly separated from one another. To clarify the findings mentioned above, that the unnoded forms of Cyprideis torosa appear in high salinity and the noded forms in low salinity a study area which shows a slow graduation of salinity would be desirable. Such an ideal area which can scarcely be found on European shores in such a form and extension is the “Schlei’. The Schlei is suitable for examinations in respect to the influence of different salinities on the animals. It is seldom like another water on the shore of Schleswig-Holstein, because salinity de- creases more or less regularly on the entire length of the Schlei. The Schlei (Text-fig. 5) extends about 40 km inland from the Baltic Sea and is a narrow, commonly 500-800 m wide, relatively shoal indented water with a water-way of 4 to 5 m depth; the salinity decreases more or less regularly on its entire length from 140/00 to respectively 20/00. According to the classification of the “Venice system” there is always mesohaline water in the entire Schlei region. Schafer (1953) from observations based on his data, and also those taken from the literature, thought the upper limit for the existence of the noded form to be a salinity of 50/00. Such a condition is not substantiated by my samples of the Schlei. I observed the noded form in the entire region of the Schlei that is also beyond the 50/oo limit, even in the outer Schlei where there is an average salinity of 13 to 150/00. Text-fig. 6 shows the distribution of the noded and unnoded forms within particular stations. There are noded and unnoded forms in all stations, station 10 excepted. Text-fig. 6 shows also that the proportion of noded to unnoded specimens shifts with increasing distance from the Baltic Sea in favour of the noded form. Suddently in the range of 50/oo (station 1 and 2) 990/00 of the males and 980/00 of the females here are noded, whereas in the other station{s 3 to 11 (middle and outer Schlei-region) the unnoded form of Cyfrideis torosa predominates in both sexes. The course of the curves for both sexes is approxi- mately the same as to the decrease at about 5o0/oo salinity and the increase 210 B. VESPER Station 9 Station 8 Station 7 Station 6 Station 5 = z Station 2 44 Station 1C ~ b 7S ntl jon 4 \ Station 4 Staton STS 6 SSD Ee (6) 10 km Text-figure 5. Location of sampling stations in the Schlei. which is repeated twice in the range of 6 to 9%o and the increase at station 11. The ranges of salinity at about 5%o and between 6 to 9%o seem to be critical ranges. The table (Table 1) shows the numerical relation of males and females, of noded and unnoded individuals, and serves for completion of the curve shown in Text-fig. 6. As seen from the Text-fig. and the Table the noded specimens can be observed in the entire region of the Schlei. But number and intensity of the nodes are different in the single regions of the Schlei. In the outer region of the Schlei, the noded specimens of station 11 (both males and females) have node number one very weakly developed only on the right valve, whereas the left valve is unnoded. Station 10 had only unnoded specimens. The males at station 9 have only node number one either on both valves or only on the right valve. The same is true for the females, and node number one may only be developed very weakly on the left valve so that it looks as if this node is rising. Station numbers 8 to 1 of the middle and the inner Schlei are distinguished, unlike stations 11 to 9 of the outer Schlei just discussed, by generally stronger noded specimens. Nop1Inc oF CyPRIDEIS TOROSA 241 Quota of noded specimens SEGuMION Ge st 2 435 56 7 8 9 10 1 Text-figure 6. Percentage distribution of males and females of the noded form of Cyprideis torosa within the sampling stations of the Schlei. (July, 1969). Salinity values are in parts per thousand. 21zZ B. VESPER Table 1. Distribution of males and females of the noded and unnoded form of Cyprideis torosa within the sampling stations of the Schlei (July, 1969). Males Females Salinity unnoded noded unnoded noded Station %oo quantity quantity % quantity quantity % ila 13,2 214 18 8 478 16 3 10 13,1 all _ 0 all _— 0 9 14,5 666 13 2 639 13 24 8 Ta 57 2 3 115 4 3 7 8,0 198 29 13 421 41 9 6 5,3 162 8 5 703 36 5 5 6,2 57 4 7 120 30 20 4+ 6,9 235 11 +4 693 29 4 3 Asif iS 3 Z 988 9 1 2 1,8 20 140 88 19 303 94 1 Zyl 5 396 99 15 711 98 In stations 8 to 1, there appear still weakly noded forms, represented by weak node number one and smooth left valve, as this is also true in the speci- mens of the outer Schlei. It could be summarized for the Schlei region that: 1. In the entire Schlei region from 2 to 14%o0 there appear noded and unnoded specimens. 2. Above the limit of 5%o salinity the unnoded form predominates, below the 5%o limit almost exclusively the noded form of Cyfrideis torosa is present. 3. Number and intensity of nodes in the stations of the outer Schlei (station 11 to 9) are lower than those in the middle and inner Schlei (station 8 to 1), although in both latter regions animals with a lower number of nodes and weaker nodes may appear. 4. A complex of station 11 to 9 in which the noded specimens have developed weak and few nodes, mostly only one node, is opposed to a complex of station 8 to 1, in which the noded specimens mostly have developed several and strong nodes. The extent to which one can speak of an increase of the number of nodes and the intensity of the nodes on decreasing salinity is obscure; in any case there is no straight rise. Another of my study areas on the shore of the Baltic Sea was the lake “Kleiner Binnensee’”’. This lagoon is protected by two dikes against the Baltic Sea and drains through an outlet (waste-pipe with a flood-gate) into the Baltic Sea. The salinity is never above 40/00; this is supported by the data from the literature, and it is relatively constant as the salinity fluctuations are rather low. Unnoded and noded specimens of Cypfrideis torosa also appear in the Kleiner Binnensee. It is striking that the noded specimens of both sexes have Nopinc oF CyYPRIDEIS TOROSA 213 in most cases developed only one node (number one). In general this is con- fined to the right valve, it also appears on both valves. In any case, it is very weak, sometimes even weaker than in regions of the just mentioned outer Schlei with its salinity of 13 to 150/00. Sporadically, node number three instead of node number one appears. It is striking that extremely weakly noded specimens appear in a salinity of never more than 40/oo and in relatively constant conditions which are present in the Kleiner Binnensee. In respect to the stations of the Schlei with similar salinity, one should expect consider- ably stronger noded specimens. In the region of the shore of the North Sea, ditches of the Friedrichskoog and the Neufelder Koog behind the dike had been investigated. These ditches have a water-surface of about 4.50 m breadth. The salinity of these ditches is about 40/00, and therefore is similar to some regions of the Schlei and of the Kleiner Binnensee. In the stations examined in the ditches, all specimens of Cyprideis torosa are unnoded, although, the salinity only is about 4%o as mentioned above. In consideration of some stations of the Schlei and those of the Kleiner Binnensee, one should expect both unnoded and noded animals. In summary: 1. Nodes appear in a range of salinity between 2 and 150/00. The upper limit for the existence of noded specimens at the 50/oo limit mentioned by Schafer is by far too low. 2. The intensity of the nodes is different in the particular salinity ranges. At higher salinity, the intensity of the nodes is distinctly weaker than at middle or very low salinity, although animals with weak nodes may also appear in the latter two. Moreover the intensity of the nodes is different in the different regions studied, in spite of nearly the same salinity. While in the Schlei at a salinity of 40/00 noded and unnoded specimens appear, the noded specimens of the Kleiner Binnensee only have one weak node on the right valve at about the same salinity; all specimens living at the same salinity in the North Sea ditches, contrary to expectation, are unnoded. The nodes may occur differently strong on both valves. They are nearly always stronger on the right valve than on the left; they may be limited only to the right valve. 3. As to the number of the nodes, different combinations of nodes may be developed, although their location seems to be constant. Some nodes re- peatedly show different extensions. DISCUSSION Extensive consideration has been given to explanations of this phenomenon. The possible causes of this feature range from physiological to genetic fixation. While Triebel (1941) supposed that the nodes increase the cavity (volume) between the two shells and, therefore, noding is to be regarded as an adaption to the lower specific gravity of brackish or freshwater, Sandberg (1964) considers this theory insufficient, for nodes would have to lie within the 214 B. VESPER area of the muscle scars what does not always prove right. Moreover the nodes examined by Sandberg were not filled with body tissue but were reflected internally by corresponding depressions of equivalent size. Sandberg concludes “that noding in brackish-water and in freshwater species has different causes”, but does not realize “why the nodes must be regarded as functional structures (e-g., regulators of specific gravity). The nodes may well be non- functional responses to an altered, perhaps abnormal, environmental factor” (p. 41). According to Sandberg, noding is negatively correlated with salinity. Due to the decrease of salinity the chemical constituents (organic as well as inorganic) of the environment are in lesser amounts; perhaps occasionally they are nearing a critical minimum level. Sandberg thinks it possible that noding is a physiologically controlled, abnormal but not pathological reaction to a deficiency in the changed environment. The variation in strength of nod- ing, let us suppose, results from each animal showing different reactions to the environment. According to the results cited herein that noded forms appear below a salinity of 50/00, noding on Cyprideis torosa has to be con- sidered, according to Hartmann (1964), as modificatively produced pheno- typical characteristic. According to Hartmann it is surprising (translated by the writer) that “the unnoded form also appears in water with low salinity and in nearly freshwater where, if such a concentration of salinity has a modifying effect, the noded form would be expected. Beside the modifying effect of low salinity other factors are due to participate in the occurrence of noding’. A long continuing conservation argues against a phenotypical modification of long duration. ‘Perhaps modificative and genetic fixation effect in the same direction’ (Hartmann, 1964, p. 65). During the symposium at Pau (France, 1970) Kilenyi expressed the opinion (personal communication from Hartmann) that noding is a genetically fixed dominant characteristic. Opposed to this assumption, however, is the proportion of the unnoded and noded individuals in the different populations found during this study. It would be difficult to imagine how a characteristic which is only genetically and not (also) influenced by the milieu should be used in palaeontology as an indicator of marine coastal area. If noding is a genetically controlled phenomenon, it will most probably be a polygene system. One or several specifically effecting gene-complexes and components influenced by the milieu lead to the formation of a phenotypic characteristic, in which not the characteristic but the norm of reaction to the milieu is inherited. Although I could state that noding does not appear, as so far believed, in a fixed salinity of 50/oo but that this phenomenon occurs slowly, and if correlated with decreasing salinity, then the question of the causality of noding goes unanswered. As discussed earlier in this paper, noding does not appear in all types of waters regularly with decreasing salinity (respectively at the same low salinity). A decisive factor could particularly be the content of CaCO; of the particular waters. The table (Table 2) shows how the amount of CaCOsz is distributed at the stations studied. Thereafter at higher concentration of NopInc oF CypriIpEIS TOROSA 215 Table 2. Amount of calcium (mg/l) in the different regions Schlei station 11 205 10 181 9 182 8 132 7 135 6 141 5 124 4 125 3 133 2 94 1 78 Kleiner Binnensee station max. min. mean 1 113 91 108 2, 119 32 90 3 115 36 87 region of the shore of the North Sea Neufelder Koog station max. min. mean 1 183 85 137 2, 171 87 138 Friedrichskoog station max. min. mean 1 268 145 196 2, 296 123 165 3 205 1 N7/ 148 4 153 75 122 CaCOs only weakly noded specimens appear, at lower concentration strong noded examples appear. A physiological control of noding, 7.e. an influence of environmental factors, either salinity or the amount of CaCOs, within sensitive periods of the animals could be imagined. REFERENCES Hartmann, G. 1964. Das Problem der Buckelbildung auf Schalen von Ostracoden in dkologischer und historischer Sicht (Mit Bemerkungen zur Fauna des Trasimenischen Sees). Mitt. Hamburg. Zool. Mus. Inst. (Koss- wig-Festschrift), pp. 59-66. Sandberg, P. 1964. The ostracod genus Cyprideis in the Americas. Stockholm Contr. Geols 12 .ppal-178: 216 B. VESPER Schafer, H. W. 1953. Uber Meeres- und Brackwasserostracoden aus dem Deutschen Kiistengebiet mit 2. Mitteilung iiber die Ostracodenfauna Grie- chenlands. Hydrobiologia, 5, pp. 351-389. Triebel, E. 1941. Zur Morphologie und Okologie der fossilen Ostracoden. (Mit Beschreibung einiger neuer Gattungen und Arten). Senckenbergi- ana, 23, pp. 294-400. Bernd Vesper Zoologisches Institut und Zoologisches Museum 2000 Hamburg 13 Papendamm 3 Germany DISCUSSION Dr. P. A. Sandberg: What about the possibility of a genetic fixation of the nodes as suggested by Kilenyi? Dr. Vesper: I think that the position of the nodes is genetically fixed but the intensity of the nodes will be controlled by environmental factors. Dr. R. Reyment: I found in our work in the Niger Delta that one has to be very careful about ecological measurements. In upper littoral sediment, you have one set of ecological conditions, that is in the interstitial pore water; in the water immediately overlying the sediment, results that differ quite considerably are obtained. The ostracods living in the sediments are subject to quite different environments from those that live on the surface. Dr. H. Léffler: I think you really could prove your ideas by culturing the species. Dr. Vesper: Yes, I am making experiments in culturing the species. Dr. M. C. Keen: I take it from your diagrams that you didn’t sample higher salinities ? Dr. Vesper: No, I did not. Dr. Keen: I ask this because Kilenyi (Tax., Morph., and Ecol. of Recent Ostracoda, Ed. J. W. Neale, 1969, p. 91) mentioned an increase in nodosity from marine waters down to a salinity of 20 o/oo, then a decrease in nodosity going into lower salinities. In other words, not a simple relationship between nodosity and decrease in salinity. VARIATION IN PREDATION BEHAVIOR OF OSTRACODE SPECIES ON SCHISTOSOMIASIS VECTOR SNAILS} I. G. Soun and L. S. KornicKer U.S. Geological Survey; Smithsonian Institution ABSTRACT Laboratory experiments using 1- to 3-day old Biomphalaria glabrata (Say, 1818) and species of ostracodes belonging to the genera Cypretta, Cypridopsis, Heterocypris, and Cypricercus indicate that the rate of of predation varies with the ostracode species used. RESUME Les expériences de laboratoire utilisant des Biomphalaria glabrata (Say, 1818) agés d’un a Trois jours et des espéces d’ostracodes appartenant aux generes de Cypretta, de Cypridopsis, de Heterocypris et de Cypricercus indi- quent que la fréquence de prédation varie entre les especés d’ostracodes employées. INTRODUCTION The life cycle of the blood fluke that causes schistosomiasis (bilharziasis) in humans and other mammals is shown in Text-figure 1. Diseased animals excrete eggs, which develop in water into free-swimming miracidiae. These miracidiae enter the body of vector snails where they metamorphose into sporocysts which in turn produce many cercariae (free- swimming blood flukes) that leave the snail. After contact and penetration of the skin or hide of mammals, the cercariae invade certain organs where they multiply. Text-figure 1 suggests two stages during which the life cycle of the blood fluke may be interrupted: 1) The miracidiae may be eliminated through sanitary methods that prevent the eggs from developing in waters that contain the vector snail, and the development of worms in the infected animal may cercariae ~ > > > SS p= a Text-figure 1. Life cycle of the blood fluke that causes schistosomiasis. Four methods which may cause an interruption in the life cycle are indicated. 1Publication authorized by the Director, U. S. Geological Survey. 218 I. G. Soun anv L. S. KornicKer be prevented by drugs; 2) the vector snails may be controlled by chemical or biological means. Ostracodes have been suggested as one of many potential biological controls. Many laborateries breed vector snails to obtain cercariae in order to infect laboratory animals for testing the effectiveness of drugs. Bruce and Radke (1971, p. 2) reported that the Walter Reed Army Institute of Research established a Composite Drug Screening Unit in Japan in which to test 8,000 to 10,000 drugs per year against Schistosoma mansoni in rodents and primates. During 1969, that facility alone produced about 40,000 snails (ibid, p. 65, fig. 25). These snails produced 15 to 20 million cercariae per week. Ostracodes have been found to be a pest in the snail-breeding operation because they decimate aquarium snail populations (Van der Schalie, 1970, p. 6)). Thus, ostracodes have a negative effect in this phase of schistosomiasis research, and studies have been made to eliminate ostracodes from snail aquaria. HISTORICAL REVIEW The first published record of ostracodes killing snails was by Deschiens, Lamy, and Lamy (1953); they described how Cypridopsis hartwigi Miiller, 1900, attacked and killed snails in laboratory aquaria maintained for breeding snails to be used in the study of schistosomiasis. The following year, Deschiens (1954) described how the ostracodes attacked the snails Bulinus contortus (Michaud, 1829) and Planorbis glabratus Say, 1818 (= Biomphalaria glabrata) like a swarm of bees, and speculated that this ostracode could be used for the biological control of these schistosomiasis vector snails. Watson (1958, p. 868), quoting Wright (personal communication, 1957) stated “Cypridopsis is normally a detritus-feeder. If no other food is available in an aquarium it will eat the faecal pellets of the snails present, even going so far as to nibble them from the snail’s anus. The irritation thus produced causes the molluscs to retract and cease feeding. The impression is thus created that the crus- taceans are actually attacking the snails when in fact they are merely seeking their faeces as food”. Lo (1967) experimented with Cypridopsis vidua (O. F. Miller, 1776) collected near Ann Arbor, Michigan, and 2-day-old Biomphalaria glabrata and found that the ostracodes kill the snails in the laboratory. He reported that snails in eight additional genera were affected by the ostracodes and that the snail species varied in their tolerance to the ostracodes. He concluded, however, that ostracodes could probably not be used in nature as a biological control. Kawata (1971) noted that in his cultures of B. glabrata, an ostracode species [Cypretta kawatai Sohn and Kornicker, 1972b] was an efficient preda- tor on young snails. The ostracodes so irritated adult snails that the snails left the water, then weakened, and either died or returned to the water and were killed by the ostracodes. Sohn and Kornicker (1972a) reported on the basis of laboratory experiments that Cypretta kawatai is an effective predator on 1- to 3-day old Biomphalaria glabrata. OsTRACODES ON SCHISTOSOMIASIS VECTER SNAILS 219 EXPERIMENTAL DATA We experimented with Heterocypris incongruens (Ramdohr, 1808) and Cypridopsis cf. C. vidua (O. F. Miiller, 1776) from Lover’s Lane Pond, Dum- barton Oaks, Washington, D.C., and Cyfricercus sp., probably new, grown in our laboratory since June 1969 from dry mud collected in Lake Colombo, Ceylon, by Dr. A. S. Mendis, Department of Fisheries, Sri Lanka. We used 1- to 3-day old snails of the red mutant (albino) strain of Biomphalaria glabrata. Our experimental procedures have been described previously (Sohn and Kornicker, 1972a, p. 1258, paragraph 2). The results of additional experiments are shown in Table 1; these are combined with previous experiments in Text- figure 2. Table 1. Number of days to 50 percent mortality of snails, using Heterocyfris, Cypridopsis, and Cypricercus. Number of Days to 50 percent Species of Ostracoda ostracodes snail mortality Heterocypris incongruens 500 0.50 Cypridopsis cf. C. vidua 500 3.28 Cypricercus sp. 500 47° “ No dead snails and more than 600 ostracodes; experiment discontinued. Text-figure 2 includes data on C. wvidua derived from Lo (1967). We calculated the abundance of ostracodes from Lo’s data on the basis of culture dishes 90 mm in diameter (G. M. Davis, Philadelphia Acad. Science, oral communication on size of dish, July, 1972), and an estimated water depth of 20 mm. “Equivalent number of ostracodes/m2” was calculated by dividing the number of ostracodes in each experiment by the area of the dish, and the quotient was extrapolated to a square meter. The data on Cypretta kawatai are from Sohn and Kornicker (1972a). Because the ordinate on the graph in our previous study (1972a, fig. 1) represented the number of ostracodes used, we did not include on it experiments with parameters other than five snails and dishes with 80-mm diameters. These data (1972a, table 1) are included in Text-figure 2. On this graph we use population density as the ordinate in order to com: pare roughly the laboratory data with population densities in nature. In out experiments we used the equivalents of 5,000 to 100,000 ostracodes/m2. These are within the ranges of some abundances recorded in nature. Luferova (1968) cited a peak of 18,000 specimens/m? of Cyfridopsis vidua in September, 1965 in the Rubinsk Reservoir, USSR, and quoted references to Mordukai- Boltovskoi (1937) who recorded 50,000 ostracodes/m? as usual in Taganrog Bay in the Sea of Azov and as many as 230,000 ostracodes/m? during periods of maximum development. Dr. M. N. Gramm, Vladivostock, USSR, informed us (letter, Aug. 17, 1972) that the species involved is Cypridcis littoralis (Brady, 1868 [1869]). Barthelmes (1965) recorded as many as 9,000 to 22,000 speci- mens/m* of H. incongruens in certain carp ponds at Schwerin, Germany. 220 I. G. Soun anv L. S. KornicKer Number of Ostracodes per per Square meter Miuilliliter 100,000 5.00 | 4 ) (LOSOnof) 90,000 4.50 | reached 7 Cypretta kawatai l 80,000 4.00 - 1 | Cypridopsis spp. 70,000 3.50 ao OOF 3 60,000 3 é | 2 50,000 250+ ee 40,000 2.00 30,000 I.50F 9 c) | \ 20,000 1.00 @ A \ \ N AL BR 10,000 0.50 pine dei — — controls 10) 0.00 fo) io 20 30 40 50 50 percent snail mortality (days) Text-figure 2. Number of days to 50 percent mortality of snails. Square — Heterocypris incongruens, circle — Cypretta kawatai, open triangle — Cyfri- dopsis cf. vidua, filled in triangle — Cypridopsis vidua, diamond — Cypricercus sp., LD50 = live-dead ratio. Second column should read “per Milliliter.” The data on C. kawatai and the controls represent experiments that were duplicated 5 or more times, with 5 to 50 snails, 25 to 500 ostracodes, and dishes 80 to 190 mm in diameter. The number of snails in the experiments had no effect on the rate at which they died; the death rate was controlled primarily by the ostracode density. The curve for Cyfridopsis spp. is based on our experiment with C. cf. C. vidua and those by Lo (1967). This curve was drawn subparallel to the curve for C. kawatai. Although we performed only two experiments with Heterocypris incongruens, the results suggest a curve very close to that of C. kawatai. Our single experiment with 500 speci- mens of Cypricercus sp. was terminated after 47 days, at which time all the snails were alive; the average number of days for the snails to reach 50 percent mortality in the controls was 46. OsTRACODES ON SCHISTOSOMIASIS VECTER SNAILS 221 The results of the experiments shown on Text-figure 2 suggest that Heterocypris incongruens may be as effective a predator as C. kawatai, that Cypridopsis spp. may be slightly less effective, and that Cypricercus sp. may have no effect on snail mortality. Additional experiments are necessary to support this hypothesis. REFERENCES CITED Barthelmes, Detlev 1965. Heterocypris incongruens (Ramdohr) 1808 (Crustacea, Ostracoda) als fakultativer Rauber und seine mégliche Bedeutung in Karp- fenteichen. Fischerei, Band 13, N.F., Heft 14, pp. 1-2. Bruce, J. I., and Radke, M. G. , 1971. Cultivation of Biomphalaria glabrata and maintenance of Schis- tosoma mansoni in the laboratory, Part I, in Culturing Biomphala- ria and Oncomelania (Gastropoda) for large-scale studies of schistosomiasis. U.S. Army Medical Depart. Activity, Japan, Bio- Medical Report, 19, 406th Medical Laboratory, pp. 1-84. Deschiens, R. 1954. Mechanisme de l’action lethale de Cypridopsis hartwigi sur les mollusques vecteurs de bilharzioses. Soc. Pathologie Exotique, Bull. 47, pp. 399-401, 2 figs. Deschiens, R., Lamy, L., and Lamy, H. 1953. Sur un ostracode prédateur de Bullins et de planorbides. Soc. Pathologie Exotique, Bull. 46, pp. 956-958, 2 figs. Kawata, Kazuyoshi 1971. Survival studies of Biomphalaria glabratus in polluted waters. Rockefeller Foundation grant GA MNS 6846, Technical Report, 44 pp., 10 figs. Lo, C.-T. 1967. The inhibiting action of ostracodes on snail cultures. Amer. Mic- ros. Soc., Trans. vol. 86, No. 4, pp. 402-405. Luferova, L. A. 1968. K faune Ostracoda Rybinskogo Vodokhranilischa. Akad. Nauk SSSR, Inst. Biologii Vnutrennikh Vod, Trudy No. 17, pp. 76-81, “Nauka,” Leningrad (Translated, 1959, by R. H. Howland, Bu- reau of Sport Fisheries and Wildlife, Washington, D.C., 9 mimeo- graphed pages). Mordukai-Boltovskoi, F. 1937. Composition and distribution of the benthos in Taganrog Bay. [Sostav i raspredelinie bentosa v taganrogskom zalive]. Raboty Dono-Kubansk. nauchn. rybn. stantsii, No. 5. Rostov (not seen). Sohn, |. G., and Kornicker, L. S. 1972a. Predation of schistosomiasis vector snails by Ostracoda (Crus- tacea). Science, vol. 175, pp. 1258-1259, 1 fig., 1 table. 1972b. Cypretta kawatai, a new species of freshwater Ostracoda (Crus- tacea). Biol. Soc. Washington, Proc., vol. 85, No. 26, pp. 313-316, 3 figs. Van der Schalie, Henry 1970. Studies of the intermediate snail hosts of Oriental and African schistosomiasis. U.S. Army Medical Research and Development Command, contract DA-49-193-MD-2651, Annual Progress Report, 28 pp., 31 figures. Watson, J. M. 1958. Ecology and distribution of Bulinus truncatus in the Middle East. World Health Organization Bull., 18, pp. 833-894. 222 I. G. Soun anv L. S. KornicKer I. G. Sohn, L. S. Kornicker U.S. Geological Survey, National Museum of Washington, D.C. 20244 Natural History, Smithsonian Institution, Washington, D.C. 20560 DISCUSSION Dr. R. H. Benson: Greg was good enough to give me some specimens of his Cypretta species, of which I showed a diagram of the marginal structure this morning. The species Cyfretta, which all have marginal septa, have an inter- esting distribution in that they are rather disjunct throughout the world. Cypretta is very much like Cypridopsis except that it has an unusually thin shell. It’s identified primarily by the fact that it has accessory struts or septa in and along the margin. To bring a taxonomic query to this discussion, I’m suggesting that Cypretta may not be taxonomically distinct. The important diagnostic character, that is the presence of struts, is simply a mechanical adaptation near the margin for increasing the strength of a very thin shell in order to provide resistance against buckling in this sensitive area. So that, in fact, this disjunct distribution of Cyfretta may be an expression of a very simple mechanical adaptation which is morphologically convergent in many parts of the world. Dr. Sohn: I believe that the present geographic distribution of Cyfretta is partly explained by the fact that the genus is a member of the highly adaptable ricefield biota. Dr. Kornicker and I have ample evidence that Cyfretta was introduced with the snail Biomphalaria glabrata (Say, 1818) to laboratories in Washington, then to laboratories in Baltimore, and later to our laboratory. I recently saw an adult Cypretta feeding inside the gelatinous cluster of snail eggs. Because some of the species in Cyfretta can reproduce parenthogenetically, it is conceivable that they, as well as other ostracodes could have attained considerable geographic distribution through the water casks of sailing ships. The septate anterior is not the sole character that differentiates Cypretta from Cypridopsis, these genera differ primarily in the development of the furca. This session is not the appropriate time to discuss how much weight to place on what character for generic discrimination. This topic may profitably serve as a basis for a future symposium. The suggestion that the development of septate structures in Cyfretta is simply a mechanical adaptation for increasing the strength of a very thin shell is not convincing because there are no precise measurements on the rela- tive shell thickness of Cypretta and Cypridopsis. Oncocypris Miiller, 1898, ap- pears to have a thicker shell than Cypfridopsis, and this genus also has septate margins. Stenocypris Sars, 1889. has septate margins, and this genus is archi- tecturally and morphologically quite different from Cypridopsis. Discussion of Film by I. G. Sohn and L. S. Kornicker showing Ostracodes feeding on Schistosomiasis Vector Snails Dr. L. D. Delorme: Have you removed the mucus from the snails and placed it with the ostracodes to see if this is what attracts them? Dr. Sohn: No. Anonymous: Would they go after dead snails just as they do after live snails? Dr. Sohn: Yes. Ostracodes are known to eat dead snails. The unresolved ques- tion is whether or not ostracodes actually kill snails. Research in cooperation OsTRACODES ON SCHISTOSOMIASIS VECTER SNAILS 223 with Dr. J. I. Bruce, Schistosomiasis Research Unit, Department of Medical Zoology, Walter Reed Army Institute of Research, may answer that question. We plan to tag snails by feeding them C-14 glucose. The snails will then be starved in order to eliminate fecal pellets which ostracodes are known to eat. We will then introduce ostracodes into the snail container, and will remove dead snails. Should the ostracodes become tagged, we will know that they kill snails. Dr. L. E. Petersen: What are the possibilities that the ostracodes are attracted to the snail by the movement of the snail? Dr. Sohn: You may have noticed that the elongate ostracode (Cyfricercus sp.) did not behave as though he was attracted by the snails, and that the fat ostracode (Cypretta kawatai) was more interested in the snails. As I said yesterday, we have just barely scratched the surface of ostracode-snail preda- tion, and that there is a great deal of research to be done. We will gladly supply starter colonies of ostracodes that are available to us to any laboratory interested in additional experiments. Mr. J. H. Baker: Do you get a growth of algae on the gastropods which could attract the ostracodes? Their movement around the gastropod would disturb it, causing it to retract, and thus eventually death. Dr. Sohn: We did not see algae on the 1- to 3-day old snails used in our ex- periments. We used also older snails for making the motion pictures in order to see whether or not the ostracodes behaved differently. ES . a 4 MK oe det ee a dea <' 1 : Lat ra "bh LUGAR nk SoA RAND re blued ' : ! i Pot ve bah | sii? hi iyt PRE i a rapt b hus yi Aa Ty fy i ‘ 4,038 et re bik ton Ber iis arts | Mu anid 7. iol site tia 1 viblh oath hana: ‘ae id bat 1 rent sity ’ ;) anit ot ¢g ethene ae 4) wh 1S! Ay SA) (eter ie Dai! i re ry ager prods ® ny oe eThite ts std MORPHOLOGY OF CYPRIDOPSIS VIDUA (0. F. MULLER): VARIATION WITH ENVIRONMENT Rocer L. KAESLER The University of Kansas ABSTRACT Study of the correlations of six morphological characters of Cypridopsis vidua (O. F. Miller) with parameters of the physical and chemical environ- ment was based on repeated sampling of five farm ponds in eastern Kansas. Morphological data were analyzed by nested analysis of variance and Student- Newman-Keuls a posteriori tests. Relationships among the environmental para- meters and between morphological characters and the environment were analyzed using correlation coefficients, distance coefficients, and cluster analysis. The statistical analyses showed that many of the very subtle correla- tions between morphological characters and environmental parameters, though slight, are highly significant in a statistical sense. Evidence suggests that both antagonistic and synergistic effects of environmental parameters on each other may influence the response of morphology to differences in the aquatic en- vironment. Cypridopsis vidua is interpreted as a morphologically very plastic species. If morphological plasticity is an indicator of physiological adaptability, the success of C. vidua in populating the freshwater environment could be ac- counted for readily. Moreover, ignoring for the moment problems of speciation one encounters with parthenogenetic organisms, if the morphological characters that have been used to discriminate species of Cyfridopsis show as much varia- tion as the characters used in this study, some of the many species in the genus may be synonyms. Such high variability within a species has important implica- tions for its use in the study of plate tectonics and continental drift. RESUME L’étude des corrélations des six caractéres morphologiques du Cyfridopsis vidua (O. F. Miiller) avec les paraméters de l’environnement physique et chimique s’est fondée sur l’échantillonnage répété de cing étangs du Kansas oriental. On a analysé des données morphologiques par l’analyse emboitée du désaccord et par des épreuves Student-Newman-Keuls a fosterior. On a analysé les rapports parmi les paramétres environnants et entre les caractéres morphologiques et l’environnement. en employant les coefficients de corrélation et les coefficients de distance aussi bien que ]’analyse d’un groupe. Les analyses statistiques ont montré qu’un grand nombre de corrélations subtiles entre les caractéres morphologiques et les paramétres environnants, bien que peu con- sidérables, sont trés significatives au sens statistique. L’évidence suggére que les effets antagoniques et synergistiques, tous deux, sur les paramétres en- vironnants l’un sur |’autre, peut influencer la réaction de la morphologie aux différences dans l’environnement aquatique. On interpréte Cypridopsis vidua morphologiquement comme une espéce trés plastique. Si la plasticité morphologicale indique la faculté d’adaptation physiologique, on pourrait facilement se rendre compte de la réussite du C. vidua a peupler |’environnement d |’eau douce. De plus, en ne tenant pas compte pour le moment des problémes de détermination des espéces que |’on rencontre avec des organismes parthenogenetiques, si les caractéres morphologi- ques que l’on a employés, afin de distinguer des espéces du Cyfridopsis, montrent aussi de variation que les caractéres employés dans cette étude, il se peut que quelques-unes de ce grand nombre d’espéces dans le genre soient synonymes. Une telle grande variabilité dans une espéce tient des implications importantes pour son emploi dans |’étude de plaques tectoniques et des apports continentals, 226 R. L. Karsier INTRODUCTION The study of the ecology and paleoecology of Ostracoda has been directed primarily toward determining the presence or absence of species of ostracodes in an area, the relative abundances of species, and the tolerances of species to various parameters of the physical and chemical environment. Studies of these kinds, along with increasingly refined taxonomy and biogeography, have mark- ed our science and have accounted for most of its considerable progress during the past century. While this progress has been underway, one aspect of the study of Ostracoda has received significantly less attention until very recently than the kinds of research mentioned above, enough less, in fact, that it could be regarded as a neglected dimension of our science. I refer, of course, to the study of intraspecific variation of morphology. The existence of variability within species has long been recognized. In- deed, it is inherent in ostracodes which we very properly study as organisms rather than as sedimentary particles. Nevertheless, except for sexual di- morphism, intraspecific variation of merphology has usually received only passing mention rather than systematic study, and its discussion has often been limited to effects of neoteny or postmatural molting (see Szczechura, 1971, for an interesting evaluation). Notable exceptions to this rule are the stimulating discussions of salinity and nodosity in Cyprideis (e.g., Sandberg, 1964; Kilenyi, 1971). Several other examples could serve nearly as well, such as Leptocythere or Ilyocypris bradyi and I. gibba. The study of intraspecific variation of morphology is one aspect of the growing field of population biology. As population biology has ascended, it is not surprising that students of the Ostracoda have concerned themselves more in recent years than ever before with intraspecific variation of morphology (Barker, 1963; Kilenyi, 1971; Szezechura, 1971; Kaesler, 1971a, 1971b; Cadot and Kaesler, 1973). For greatest success, such research should be founded on careful study of the fundamental unit of evolution, the biological population. Moreover, it should consider both the sources and the causes of the variation under study. The purpose of my study is to test the hypothesis that morphology of local populations of Cypridopsis vidua varies consistently with differences in para- meters of the physical and chemical environment. The results will show, first, statistically significant differences among some local populations of the species; second, variations in the aquatic environments of the ponds; and, third, correlations of morphological characters with environmental parameters. Finally, brief mention will be made of possible synergistic and antagonistic effects between chemical constituents of the water in which the ostracodes lived. To speak of biological! populations of an obligate parthenogenetic organism such as Cypridopsis vidua is somewhat irregular. The population of C. vidua in a single pond is in no sense a quasi-isolated, intrabreeding biological population. One of the primary advantages parthenogenesis gives its prac- titioners is the ability for a single individual accidentally carried to a new MorruHo.ocy oF CyPpRIDOPSIS VIDUA 227 locality or accidentally left behind in an old one to generate a new colony (White, 1970). It is possible, then, but not certain, that all the individuals in a given locality are genetically identical. Reasons for lack of genetic identity are presence of clones within the pond from two or more genetically different founders, mutation within a clone subsequent to founding of the colony by one or more genetica!ly identical founders, and heterozygosity of the founder leading to genetic segregation — if the species is an automictic one (7.e., having meiosis with doubling of the number of chromosomes later in life; see White, 1970). In the area studied, it seems unlikely that the colony in any pond represents only a single clone, and one can never rule out mutation. Moreover, it is too early to speculate on the importance of heterozygosity of C. vidua because little is known about its genetics, although it is difficult to conceive of sustained heterozygosity since the Oligocene other than that reintroduced by mutation, unless C. vidua shows polyploidy. For this research it has been necessary to make the reasonable but untested assumption that individuals within a pond are on the average more similar to each other genetically than to individuals from other ponds. It has not been possible, however, to ascribe the morphological differences observed either to annidation — “an adaptive correspondence be- tween the various genotypes present in the population and the alternative ecological niches present in the environment” (White, 1970, p. 238; Ludwig, 1950) — or simply to the effect of the evironment on the phenotype. As was mentioned earlier, both the sources and the causes of observed morphological differences should be determined if possible. Here sources refers to the relative magnitudes of variation within populations and among popula- tions. For example, if all local populations — here the individuals within a pond — have a very small variance, then differences among ponds will be readily apparent. On the other hand, if the populations within ponds are highly variable, detecting differences among ponds will be very difficult. Text-figure 1 demonstrates the importance of this concept for two studies involving two populations each, one study with small variances within popula- tions and the other with large variances within populations. Although the mean differences between populations are the same in both examples, the differences are much less easily detected when the variation within ponds is great. The analysis of variance is a statistical tool that is well suited for partitioning variances, and it has been used in this study. Determining causes of variation is much more difficult and usually requires the controlled conditions possible only in a laboratory study. Just as it is im- possible to ascribe morphological variation to genotypic or phenotypic dif- ferences without study of the genetics, so it is not possible to separate causes of variation from correlations among effects without eliminating the vageries that nature has introduced into the natural setting. In this research, I have studied correlations of morphological characters with environmental para- meters rather than trying to attribute the variation to particular aspects of the environment. Clearly, the understanding of variations in morphology in re- sponse to preset differences in the environment under controlled laboratory conditions requires further study in the future. 228 R. L. Kaesier . ys b Text-figure 1. Diagrammatic representation of two studies of two popula- tions each. Members of populations a and b with no overlap in morphologic characters are easily discriminated; members of populations c and d with a great deal of overlap are difficult to discriminate. Means of populations in- dicated by X. ACKNOWLEDGMENTS I am indebted to Richard B. Koepnick and Johnny A. Waters who as- sisted me with field, laboratory, and computational work. Arch H. Layman, Jr. drafted the illustrations. Mr. Waters’ and Mr. Koepnick’s participation in the research was made possible by support from the Wallace E. Pratt Re- search Fund of the Paleontological Institute, The University of Kansas. The MorpHo.Locy OF CYPRIDOPSIS VIDUA 229 research was also supported by the Kansas Geological Survey, a General Re- search Grant from The University of Kansas, and Biomedical Sciences Sup- port Grant FR07037 from The University of Kansas. All computation was done at The University of Kansas Computation Center using the Honeywell 635 computer. Specimens studied have been entered in the collections of The University of Kansas Museum of Invertebrate Paleontology. MATERIAL AND SAMPLING Cypridopsis vidua was chosen for study because it has been intensively studied in other ways previously and is a well understood, geographically widespread species (Kesling, 1951). It also occurs in great abundance in some of the ponds in the study area, the Yankee Tank Creek drainage basin (Text- figure 2). The study area, occupying about 10 square kilometers near the city of Lawrence in eastern Kansas, is the site of a multiphase environmental moni- toring program being conducted by the Kansas Geological Survey. The drainage basin is now primarily upland brome-grass farming land and pasture, and it contains more than 30 small to moderate-sized, man-made ponds used primarily for watering cattle. The area was chosen for environmental monitoring be- cause it lies in the path of expansion of Lawrence, Kansas, one of the fastest growing cities in the state. The area will almost certainly be completely ur- banized during the next ten years. Already it is the site of a sanitary land fill, and some of the farmers have begun to sell lots for houses. This study of the ostracodes from the area is a part of the environmental monitoring pro- gram. Field work was done in early July of 1970 during a nine-day interval in which no rain fell in the area. Five of the ponds (Text-figure 2) were each sampled on alternate days until they had been sampled five times. At the same time, the chemical and physical parameters of the environment listed in Table 1 were measured. Temperature, pH, conductivity, dissolved oxygen, and dissolved CO. were determined in the field, the latter three by using the Hach DR-EL system. The water samples were then refrigerated, and the other 12 parameters were determined within 24 hours after they were col- lected, also using the Hach system. Ostracodes were sampled by passing pond water and floating and at- tached filamentous algae through 20 mesh and 100 mesh sieves. Most algae were retained on the 20 mesh sieve, and ostracodes and other small invertebrates were retained on the 100 mesh sieve. After concentrating the biological material in this way, the ostracodes were placed into a small jar. The first living specimens seen swimming were collected, up to a maximum of 15 specimens per sample. Pond 31 was barren of ostracodes, although during the previous summer it had yielded abundant C. vidua. The ostracodes that were selected for study were then opened and were drawn using a camera lucida. The six morphological characters shown in Text-figure 3 were measured from the drawings. A total of 225 ostracodes were measured, distributed among sam- ples as shown in Table 2. 230 R. L. Kaesier Text-figure 2. The Yankee Tank Creek drainage basin near Lawrence, Kansas, showing locations of the five ponds sampled. MorpPuHo.ocy oF CyPRIDOPSIS VIDUA 231 METHODS OF ANALYSIS AND RESULTS VARIATION OF MorPHOLOGY The first phase of the analysis was to determine if any of the six morpho- logical characters studied vary significantly, either from sample to sample within a pond or from pond to pond. As was pointed out in reference to Text- figure 1, the problem is to determine if either the variation between samples from the same pond or the variation among ponds is sufficiently larger than the variation within a sample to enable one to detect significant differences. Alternatively, the differences that are observed may be ascribed solely to the chances of sampling. The analysis of variance is a statistical method that enables one to sub- divide or partition the variance in a set of samples in order to test hypotheses about differences in mean values of the samples. Here a nested model was chosen in order to test the null hypothesis that all samples were collected from the same statistical population and, hence, no significant differences exist either between samples from the same pond or between ponds. Recall that the sig- nificance of the differences is measured by the amount of variance within samples as compared to the amount among samples from the same pond or among ponds (Text-figure 1). It is here that partitioning the variance is im- portant. The nested model is shown verbally in Table 3. Use of a parametric statistical method such as the analysis of variance is based on the assumption that the sampling and the data meet several condi- tions. Three of the most important of these conditions for the analysis of variance are that sampling was random, that the data within any sample are normally distributed, and that the variances of all samples are the same. Several other assumptions are also required, but these were not tested. Sampling was not strictly random as is required, but neither was it purposive in any way because of the small size of the ostracodes. Any bias of the samples was intro- duced by the ostracodes themselves since only swimmers were collected. This bias is not believed to be appreciable. Most of the samples yielded normaily distributed data. Sokal and Rohlf (1969) pointed out that small departures from normality usually have little effect on the statistical tests used here. That is, the analysis of variance is said to be a robust method with respect to non- normality of the data. It is more sensitive to unequal variances. Three of the morphological characters showed heterogeneity of variance — length, height, and posterior radius of curvature. For each of these, two additional tests were computed: 1. an equality of means test that takes into. consideration the dif- ferences in variances and 2. a Kruskal-Wallis nonparametric test that is distribution free. The results of these two tests support the results obtained from the analysis of variance which, however, must be regarded as an ap- proximation only, because the data failed to meet the assumptions. Table 4 shows the percent of the variance that resides at each of the three levels in the analysis of variance. For length, for example, 67 percent 232 R. L. KAEsLEeR Table 1. Parameters of the physical and chemical environment measured and the units for each. Parameter Temperature pH Conductivity Turbidity Color Dissolved carbon dioxide Dissolved oxygen Alkalinity Total hardness Calcium hardness Magnesium hardness Iron Chloride Total nitrogen Phosphate Silica Sulfate Table 2. Number of specimens of Cyfridopsis vidua measured from sample. Date July 1, 1970 July 3, 1970 July 5, 1970 July 7, 1970 July 9, 1970 Units = OY mg/l] as NaCl Jackson Turbidity Units APHA Platinum-Cobalt Standard mg/] mg/] mg/| mg/1 mg/| mg/1 mg/1 mg/1 mg/1 mg/1 mg/] mg/] of CO: of Oz of Fe of Cl of nitrate and nitrite AsnCacOs; as ve@aCOs: as CaCO; as) CaCO: of orthophophate of SiOz of SO. Table 3. Nested analysis of variance model. Level Variance 2 Among ponds 1 Among samples, within ponds 0 Within ponds (error variance ) Explanation Differences between ponds 2, 3, 11, 19 Pond 11 12 15 15 14 14 each Differences between any of the 5 samples from any one pond Differences between any of the 2 to 15 ostra- codes in any one sample. MorpuHo.ocy oF CypRIDOPSIS VIDUA 233 Table 4. Percent of each variance component after partitioning. Asterisks indicate level of statistical significance: * = P < 0.05; ** = P < 0.01; *** — P < (0.001; tests of top three morphological characters approximate because assumptions of method not fully met. Percent of Variance Within ponds Among Among samples (error Character ponds within ponds variance) Length 2O5™ is * 67 Height 19* 1L9xt* 62 Posterior radius of curvature 1 17*** 82 Anterior radius of curvature 13** + 83 Anterior radius of curvature, inner lamella 13** 1 88 Posterior radius of curvature, inner lamella 0 2 98 of the variance is error variance, the variance in length of ostracodes within samples. Only 11 percent of the variance is accounted for by variance among the 5 samples all collected from the same pond, and 22 percent is variance among ponds. Also shown in Table 4 by asterisks are the levels of significance of the differences observed between mean values in the study. Again using length as an example, the significance level for among ponds is less than 0.01 and for within ponds among samples is less than 0.001. This means that if all samples had been drawn from the same statistical population, the probability of obtaining by chance alone due to sampling, differences among ponds as great or greater than those observed is less than 0.01. In biological work, 0.05 is ordinarily regarded as an appropriate significance level. It is ap- propriate, therefore, to reject the null hypothesis that all samples were drawn from the same normal distribution. Similarly, the probability of obtaining dif- ferences as great as or greater than those observed among samples from the same pond is less than 0.001. Recall that the analysis of variance of length, height, and posterior radius of curvature must be considered an approximation because the data do not meet the assumption of homogeneity of variances. Nevertheless, the test of equality of means (given unequal variances) and the Kruskal-Wallis test both indicated very highly significant differences (P < 0.001) when all samples are considered together. The results in Table 4 indicate that populations of ostracodes from the different ponds are statistically significantly different from each other in length, height, anterior radius of curvature, and anterior radius of the inner lamella. Neither the posterior radius of curvature nor the posterior radius of the inner lamella differ significantly. It appears either that the ostracode populations differ in their genetics, being separate biological populations in 234 R. L. KaEs_er eae Seog 1 Text-figure 3. Outline of Cypridopsis vidua showing the six characters studied: 1. length; 2. height; 3. posterior radius of curvature; 4. anterior radius of curvature; 5. anterior radius of inner lamella; 6. posterior radius of inner lamella. the sense discussed earlier, that they respond differently to different environ- ments in the various ponds, or some combination of these two possibilities. Much more difficult to explain are the highly significant differences that occur among samples within ponds. Although Kaesler (1971b) found some evidence for temporal changes in morphology among populations of adult Cypridopsis vidua, the changes were neither so dramatic nor did they occur over such a short time as these changes. In order to attempt to interpret these differences as well as to find out which samples differ from each other, Stu- dent-Newman-Keuls (SNK) a posteriori tests were computed for each morpho- logical character (Sokal and Rohlf, 1969). Note that the assumptions of the SNK test are the same as those of the analysis of variance, so the same reserva- tions should be applied to interpretation of results for the first three morpho- logical characters. The SNK test is a means of determining which groups of samples are statistically significantly different from each other. Only three of the char- acters studied showed any significant differences at all by this test, which considers all samples simultaneously. These were length, height, and radius of curvature of the anterior inner lamella. Results are summarized in Table 5 in which samples are ranked and arranged in nonsignificant subsets. Con- sidering length, for example, samples 3-3 through 2-1 are not significantly dif- MorpuHo.ocy oF CypRIDOPSIS VIDUA DISTANCE 60 30 0 P3 Pil Pll Pll Pil Pil W5 wW4 235 Text-figure 4. Q-mode dendrogram showing euclidean distances between samples as determined by the seventeen parameters of the physical and chemi- cal environment studied. P indicates pond number; W indicates day sampled in sequence. Cophenetic correlation coefficient = 0.781; clustering method UPGMA. 236 R. L. KagEsLer ferent from each other. If sample 2-2 is added to the subset, statistically sig- nificant differences occur within the new subset. Similarly, samples 3-1 through 19-3 form a nonsignificant subset and are not to be regarded as statistically significantly different from each other. VARIATION OF ENVIRONMENT Text-figure 4 is a dendrogram computed by Q-mode cluster analysis showing average euclidean distances between samples on the basis of all physical and chemical parameters of the environment that were measured. Note that for the most part samples from the same pond are closely similar and lie in the same cluster, especially samples from ponds 11 and 19. Samples from ponds 2 and 3 are mixed in the dendrogram, but most of the samples from pond 3 are in the same cluster. Lack of identity of successive samples from the same pond indicates change in the environment over the time when the sampling was done. The most notable change observed was an algal bloom underway in pond 3 during the sampling interval, but clearly other, less apparent changes must have taken place in other ponds as well in order to account for the differences shown in Text-figure 4. CoRRELATIONS OF MorPHOLOGY AND ENVIRONMENT In a study of variation of morphological characters with environmental parameters, it is helpful to deal first with intracorrelations of both the morphological characters and the environmental parameters. Where a large number of characters or parameters is used, this is particularly useful in order to reduce the number of individual correlations that must be discussed. Text-figure 5 shows results of R-mode cluster analysis of 17 chemical and physical parameters of the aquatic environment. It is apparent from the dendrogram that many parameters are highly correlated with each other. For example, turbidity and color, conductivity and alkalinity, and total hardness and calcium hardness show strong pairwise intracorrelations. If both members of any of these three pairs of parameters are strongly correlated with mor- phology of the ostracodes, then only one of them need be discussed because of the strong, pairwise correlations. It should be pointed out that some other parameters may be either more or less highly correlated than shown in the dendrogram because of distortion introduced during averaging in the cluster- ing process. Nevertheless, the dendrogram gives a close approximation to the real situation. Table 6 shows correlations among the six morphological characters studied. The highest correlation is between length and height, a not unexpected result given the relative constancy of shape of ostracode species. It is perhaps a little surprising that the correlation between these two characters is as low as it is (r = 0.751). Other characters have comparatively low correlations, some of MorpHOLoGY OF CyYPRIDOPSIS VIDUA IS7 CORRELATION d 78 010Z WoAZ JUSASZITP ATIUPOTFTUSTS HYIET*O < SeNTeA sINTosqy “JUeUOATAUS SYy FO siojoweied pue sazajqorzeyo [eoTSoToydzow usanjzoeq SqUSeTOTJJeo0o UoTIeTEALOD JuoWoW-Jonpord °*8 STIPL MorpPHOLoGY OF CyYPRIDOPSIS VIDUA 241 (P < 0.001) with length, height, and the two measures of anterior curvature. It is less strongly correlated (P < 0.05) with posterior radius of curvature margin and is uncorrelated with posterior curvature of the inner lamella. Calcium hardness and magnesium hardness are the concentrations of those two cations expressed as milligrams per liter of CaCO; and MgCOs respec- tively. They are positively correlated with the same morphological characters (Table 8), but magnesium hardness is generally more strongly correlated with all characters. These positive correlations indicate that as the concentra- tion of calcium or magnesium increases in the water, the size of the ostracodes increases. The two anions, chloride and sulfate, are highly correlated (P < 0.01 or P < 0.001) with all morphological characters except posterior radius of the inner lamella. Chloride content, however, is negatively correlated with the morphological characters, whereas sulfate is positively correlated. The difference in sign means that as chloride content increases, the measurements of morphological characters decrease, quite the opposite from the relation- ship with the sulfate radical. PossIBLE SYNERGISTIC AND ANTAGONISTIC EFFECTS A factor that may contribute to the low correlations between morphological characters and some environmental parameters and that certainly complicates their interpretation is the existence of synergistic and antagonistic effects be- tween many pairs or groups of ions. Calcium, for example, reduces the toxicity of many chemical compounds (McKee and Wolf, 1963). Interaction of ions is strongly suggested here by the fact that correlation coefficients between pairs of chemical parameters are generally much higher than correlations between morphological characters and the environment. Such relationships are difficult to detect under natural conditions and point further to the need for controlled laboratory study of the response of ostracode morphology to various environmental conditions. DISCUSSION AND CONCLUSIONS Piecing together all the relationships that have been mentioned above into a coherent story about the morphology of Cyfridopsis vidua and its dif- ferences in different environments would be a virtually impossible task. This is particularly true in light of intercorrelations and interactions between mor- phological characters and environmental parameters and given the absence of experimental data from the laboratory. We have observed variations in morphology that may be partitioned into variations within samples, variations among samples but within ponds, and variations among ponds. The variations among samples within ponds, a temporal variation, were found to be statis- tically significant for the characters length, height, and posterior radius of 242 R. L. Kaeser curvature. Variations among ponds were found to be statistically significant for all characters except those that measure posterior curvatures. We have also observed appreciable differences between all samples when compared on the basis of parameters of the physical and chemical environment of the ponds at the time the samples were collected. It is reasonable to assume that some of the variation in morphology is due to differences in the environment of the ponds. This contention is sup- ported by the highly significant correlation coefficients computed between morphological characters and environmental parameters. Length and height, for example, were found to be significantly positively correlated with concen- trations of all dissolved chemicals studied except Ov, a highly variable para- meter with a diurnal cycle; iron; silica, which is not used in the ostracode carapace; and chloride ion, with which all morphological characters had a negative correlation (Table 8). Other characters that were not so strongly related to overall size of the carapace had fewer significant correlation or cor- relations significant only at a higher level of probability. Patterns of similarity among samples of the morphological characters length and height are such that samples from ponds 2 and 3 nearly always form non- significant subsets with each other, whereas samples from ponds 11 and 19 show greatest, similarity to each other (Table 5). When one examines overall simi- larity of the samples based on all parameters of the environment that were studied, one sees a different picture (Text-figure 4). Samples from ponds 2 and 3 are indeed quite similar to each other, but samples from ponds 11 and 19 are highly dissimilar. This result suggests that rather than being controlled by similarities in the overall environment (as expressed in Text-figure 4), length and height are affected by only a subset of the parameters of the en- vironment, thus yielding a pattern of similarity based on these morphological characters that is different from the pattern of similarity of the overall en- vironment. Based on the six characters chosen for study, Cypridopsis vidua is inter- preted as a morphologically very plastic species. If morphological plasticity is an indicator of physiological adaptability, the success of C. vidua in popu- lating the freshwater environment could be accounted for readily. Moreover, ignoring for the moment problems of speciation introduced by parthenogenesis, if characters that have been used to discriminate species of Cypridopsis show as much intraspecific variation as the characters used in this study, some of the many species in the genus may be synonyms. The use of freshwater ostracodes in the study of plate tectonics and con- tinental drift has been suggested in recent years by Krommelbein (1970 and earlier papers), McKenzie (1971), and Kaesler (1971b). It is indeed tempting to envision continents as rafts moving about on the surface of the earth, each carrying with it its respective ostracode fauna. According to this model, as two continents approach each other, migration and gene flow between con- tinents may increase, resulting in increased similarity in morphology between conspecific populations of the two continents. If, however, other species of MorpuHo.ocy oF CyPRIDOPSIS VIDUA 243 freshwater ostracodes are morphologically as plastic as Cypridopsis vidua is in the area studied, one will need to be careful to develop a nested model of the variation in order to test for significant changes in morphology with move- ment of the continents. REFERENCES CITED Barker, Dennis 1963. Size in relation to salinity in fossil and Recent euryhaline ostra- codes. Jour. Mar. Biol. Assoc. United Kingdom, vol. 43, pp. 785- TIS. Cadot, H. M., and Kaesler, R. L. ; Variation of carapace morphology of bairdiacian and cytheracean Ostracoda from Bermuda. University Kansas Paleont. Contr. Paper 1971a. Preliminary report: morphological variation of Ostracoda from the Yankee Tank Creek drainage basin, Douglas County, Kansas. Kansas Geol. Sur., Bull. 202, pt. 1, pp. 5-7. 1971b. Morphological variations of Cypridopsis vidua (Ostracoda) from eastern Kansas (abstr.). Abstracts with Programs, Geol. Soc. America, vol. 3, No. 7, p. 616. Kesling, R. V. 1951. The morphology of ostracod molt stages. Illinois Biol. Monographs, vol. 21, No. 1-3, 324 pp. Kilenyi, T. I. 1971. Some basic questions in the palacoecology of ostracods. Paléo- écologie des Ostracodes (H. J. Oertli, ed.). Bull. Centre de Re- cherches Pau, §.N.P.A., vol. 5 suppl., pp. 31-44. Krommelbein, Karl 1970. Non-marine Cretaceous ostracods and their importance for the hypothesis of “Gondwanaland”’. Second Gondwana Symposium, Council for Scientific and Industrial Research, Scientia, Pretoria, South Africa, pp. 617-618. Ludwig, W. 1950. Zur Theorie der Kondurrenz. Die Annidation (Einnischung) als fiinfter Evolutionsfaktor. Neue Ergebn. Probleme Zool. KI. Fest- schr., pp. 516-537. McKee, J. E., and Wolf, H. W. 1963. Water quality criteria, 2nd ed., Resources Agency of California; State Water Quality Control Board, 548 pp. McKenzie, K. G. 1971. Palaeozoogeography of freshwater Ostracoda. Paléoécologie des Ostracodes (H. J. Oertli, ed.). Bull. Centre de Recherches Pau, S.N.P.A., vol. 5 suppl., pp. 207-237. Sandberg, Phillip 1964. Notes on some Tertiary and Recent brackish-water Ostracoda. In Ostracods as ecological and paleoecological indicators (H. S. Puri, ed.). Pubbl. Staz. Zool. Napoli, vol. 33, suppl., pp. 496-514. Sokal, R.R., and Rohlf, F.J. 1969. Biometry. W. H. Freeman and Company, San Francisco, 776 pp. 244 R. L. KaEsLer Szezechura, Janina 1971. Seasonal changes in a reared fresh-water species, Cyprinotus (Heterocypris) incongruens (Ostracoda), and their importance in the interpretation of variability in fossil ostracodes. Paléoécologie des Ostracodes (H. J. Oertli, ed.). Bull. Centre de Recherches Pau, S.N.P.A., vol. 5 suppl., pp. 191-205. White, M. J. D. 1970. Heterozygosity and genetic polymorphism in parthenogenetic ani- mals, Evolution and genetics in honor of Theodosius Dobzhansky (M. K. Hecht and W. C. Steere, eds.). Appleton-Century-Crofts, New York, pp. 237-262. Roger L. Kaesler Department of Geology The University of Kansas Lawrence, Kansas 66045 DISCUSSION Dr. R. A. Reyment: The study I made some years ago with B. Brannstrom on Cypridopsis vidua was certainly only a laboratory study of populations. We had three environments, the so-called normal one, the one in which calcium carbonate was in excess, and one in which we kept the Eh at stagnation en- vironment. Dr. Kaesler: Do you find in the stagnant environment that the ostracodes were smaller? Dr. Reyment: They became smaller: For the other two, we could not pick up differences in environmental effects. I must say a word in defense of Prof. Krommelbein. He hadn’t only based his conclusions on the ostracods he also has very strong geological information, such as structural and sedimentalogical data backing up his work. Dr. Kaesler: I would agree that Prof. Krommelbein has presented a very compelling case. Neither he nor McKenzie studied geographic variation in the sense used here. My point is that if one should decide to apply studies of ostracode variation to tests of plate tectonics, he would need to be very careful to eliminate local variations due to differences in environments. One of the interesting aspects of the study of effects of water chemistry on the morphology of Ostracoda is that there are many interactions between dissolved constituents of the water. For example, in studies with Daphnia it has been found that an increase in concentration of calcium reduces the toxicity of copper. I have some ponds that have limestone outcrops in them, so there is an abundance of calcium carbonate in the water. This could have a marked influence on the effects of the other substances dissolved in the water. MORPHOLOGICAL VARIATION IN LEGUMINOCYTHEREIS ? HODGII (BRADY), OSTRACODA (CRUSTACEA), FROM JAPAN Kuniniro [sHIZAKI Tohoku University ABSTRACT During studies of the ostracodes from shallow marine waters around Japan, it was recognized that the specimens of Leguminocythereis ? hodgit (Brady) show differences in reticulate ornamentation and valve size depending on factors prevailing in the regions in which the forms lived. To testify the significance of those differences, samples taken from three regions of Uranouchi Bay, Kochi Prefecture, Nakanoumi Estuary, Shimane Prefecture, and Aomori Bay, Aomori Prefecture are treated by a non-parametric statistical method of Mann-Whitney’s u test because of unfavourable conditions of samples. As the result, in the moulting stages of the adult-1 and adult-2, the dif- ferences of ornamentation of reticulation are suggested to be significant among the samples from the three regions by 98 percent confidence intervals of their means. The differences in dimensions of valve length and height, are signifi- cant between the samples from Uranouchi Bay and the Nakanoumi Estuary, and Uranouchi Bay and Aomori Bay throughout the moulting stages of the adult-2 to the adult instars, although that between the specimens from the Nakanoumi Estuary and Aomori Bay seems to be questionable. Judging from the data recorded, such difference may be caused by the differences in water temperature in the regions in which the forms lived, and zoogeographical variations of the Ostracoda between the Japan Sea and Pacific side of Japan. ZUSAMMENFASSUNG Wahrend Studien der Ostracoden aus den Bucht en um Japan herum, es hat gekannt, das die Formen der Leguminocythereis ? hodgii (Brady) unter Stiicken von andere Regionen sich in den Vollkommenheit der gitterartige Skulptur unterscheiden. Diese Abhandlung ist in KlappengréSe und Verhaltnisse der gitterartige Skulptur um Verschiedenheiten klar zu machen mit nichtparametrische Methode, U Test von Mann-Whitney und 98 Prozent Verlassensintervall, fiir Stiicken durch 3 Stufen aus Erwachsenen bis Erwachsenen-2 aus 3 Regionen. Das Resultat zeigt daS die Klappengréfe sich unterscheiden zwischen Stucken von Uranouchi Bucht und Nakanoumi Mindung, und Uranouchi Bucht und Aomori Bucht, aber die Verschiedenheit ist unklar zwischen Naka- noumi Miindung und Aomori Bucht; daf die Verhaltnisse der dunkle gitterar- tige Skulptur unterscheidet sich zwischen Ontogenie Stufen und zwischen Stiicken von Uranouchi Bucht und Aomori Bucht klar. Diese Unterschiede mag auf Temperatur oberem order unterem Grenz- punkte des Meerwasser beruhen, darin Ostracoden wohnen, und auf physischen und chemischen Bedingungen verschieden zwischen das Pazifik und das Japanische Meer. INTRODUCTION During studies of the ostracodes from shallow marine waters, especially embayed areas around Japan, it was recognized that in the Nakanoumi Estuary, Shimane Prefecture (lat. 35°30’ N and long. 133°10’ E), and Aomori Bay, Aomori Prefecture (lat. 40°53’ N and long. 140°50’ E), the valve sur- 246 K. IsHizak1 LEGEND Vf ; / oP, URANOUCHI BAY : > NAKANOUMI BAY AOMORI BAY ~—-—-» CURRENT SYSTEM Text-figure 1. Main current system around Japan (after Uda, 1934), and the approximate locations of (1) Uranouchi Bay, (2) Nakanoumi Estuary, and (3) Aomori Bay. face of Leguminocythereis ? hodgii (Brady) has obscure reticulation (termed “obsolete” by Brady, 1880) anteriorly in younger moulting stages. In the adult instar, however, reticulation completely covers the valve surface. On the other hand, those from Uranouchi Bay, Kochi Prefecture (lat. 33°32’ N and long. 133°30’ E) are completely reticulate even in younger moulting stages (Pl. 1, figs. 1-5, figs. 7-11; Pl. 2, figs. 1-4, figs. 6-9). VARIATION LEGUMINOCYTHEREIS ? HODGII 247 The purpose of this work is to clarify the morphological variation among the samples from the three regions. Because of the number cf individuals and inadequate distribution of many samples, judgments were made only on the three moulting stages of the adult instar to the adult-2 (Tables 3, 4), using a non-parametric method, Mann-Whitney’s u test. All the samples treated in this work were washed with tap water through a 200 mesh sieve. The writer takes this opportunity to express his sincere gratitude to Prof. Frederick M. Swain of the University of Delaware for his continuous en- couragement and critica] reading of the manuscript. SYNOPSIS OF LEGUMINOCYTHEREIS ? HODGII (Brady) Leguminocythereis hodgii was first described by Brady (1866) under the name of Cythere hodyii based on only one valve from Levant in the north- central Mediterranean Sea, and subsequently by Brady (1880) from a dredging in the Inland Sea (Setonaikai), Japan (15 fms depth). In his second report, he mentioned that the European specimen differs from that of Japan in the valve being sparingly sculptured and with obscure reticulation except for the posterior part. As mentioned by Brady (1880), it is still uncertain whether the European and Japanese specimens belong to the same species. Under the circumstances, it is noteworthy that such variations in valve ornamentation are great, even among regions within Japan, and specimens of Brady (1880) may be morpho- logically identical with the ones from Uranouchi Bay. As a detailed description and clear illustrations have been given by Brady (1880), only a few characters necessary for measurement for statistics and some new details will be given. Sexual dimorphism in this species is great: the valve of the male is longer and oblong in lateral outline; that of the female is shorter and ovate. Thus measurement for the statistics should be done on either sex. The hinge structure is holamphidont: the left valve is slightly larger than the right valve because of the so-called hinge ears developed. At 1,000 magnification, rather regular flute structure (a sort of capera- tion in Sylvester-Bradley and Benson, 1971) could be seen on the slope of muri (valve in the adult instar from Nakanoumi Estuary, Pl. 2, fig. 10). The normal pore canals, scattered near the base of muri, and surrounded by moderate rims are situated near the center of a low mound slightly ele- vated above sola, and probably free from the flute structure mentioned above (Pl. 2, fig. 10). At about 10,000 magnification, the normal pore canals are only sieve type. The normal pore canal in the adult instar from Uranouchi Bay is an “irregularly perforate sieve plate in a circular depression” (referable to Callistocythere sp. from the Pliocene of Italy fig. 12 in Sandberg and Plusquellec, 1969) (PI. 2, fig. 5). 248 K. IswizaKk1 PLATE 1 All figures are scanning electron micrographs. Figure 1-6. 13° Serial moulting stages of right valve and normal pore canal of Legu- minocythereis ? hodgii (Brady) from Uranouchi Bay (St. 79 of Ishizaki, 1968), all & 95 except for figure 6. 1. Smaller specimen of adult-3 stage, ornamented by complete reticula- tion over entire valve surface. 2. Larger specimen of adult-3 stage. 3. Specimen of adult-2 stage. 4. Specimen of adult-1 stage. 5. Specimen of adult instar. 6. Highly enlarged micrograph of normal pore canal of figure 4, & 10,000. Serial moulting stages of right valve and hinge structure of specimens from Aomori Bay (St. 14 of Ishizaki, 1971), all % 100 except for figure 12. 7. Specimen of adult-3 stage, ornamented by complete reticulation only on posterior third of valve. 8. Specimen of adult-2 stage, also obscure reticulation occupying more than anterior half of valve. 9. Specimen of adult-1 stage, obscure reticulation still discernible on anterior third of valve. 10. Inner view of right valve of adult instar. 11. Lateral view of right valve of adult instar, ornamented by complete reticulation through- out valve surface. 12. Inner view of left valve of adult instar showing the details of hinge structure, « 190. Highly enlarged micrograph of normal pore canal of figure 9 (adult instar from Nakanoumi Estuary), 10,000. Plate 1 VARIATION LEGUMINOCYTHEREIS? Hopoit VS partys. SON ait S te PUOCCLEP ETE BERE — * ~ a oe 250 K. IsHizaKk1 Table 1. Average surface water temperature of each month for Esashi (representative of Aomori Bay), Saigo (near the Nakanoumi Estuary), and Ashizuri (representative of Uranouchi Bay) (after Meteor. Agency, 1969, 1970). Month Station February April August December Esashi 4.9°C 8.0°C DIE 6.4°C Saigo 10.8°C 142°C 272°C 14.0°C Ashizuri MEAS 19.0°C 27 ele LOI Table 2. t value and its probability between left valve and right valve of 38 complete carapaces from Aomori Bay. Calculation was made after the pair comparison. t p length 6.045 <0.001 height 6.689 <0.001 O. R. ratio 0.133 <0.200 Table 3. See p. 251. Table 4. Calculated probabilities by Mann-Whitney’s u test. Probabilities less than 0.01 are taken in significant difference between samples compared. Adult-2 Adult-1 Adult Aomori | Nakanoumi| Aomori | Nakanoumi| Aomori| Nakanoumi Bay Estuary Bay Estuary Bay Estuary Nakanoumi| length <.0100 .0688 <.0100 Estuary | height <.0100 1936 2584 O.R. ratio | <.0100 <.0100 Uranouchi | length <.0100 <.0100 <.0100 <.0100 <.0100 <.0100 Bay height <.0100 <.0100 <.0100 <.0100 <.0100 <.0100 v $00°'> 4 $00°> £ os7< 010'> 010’ > 0s0°> +++ £ 00s< v 0so< £ 00s°*< ‘ad ‘d d A}I[BWI0N F60°L2 £c7 02 £90'¢ SI9'ET Oft tl T88°0T 8+0° £68°L 9b7'E cD. @ ainosqo oz aduapiyuod %¢6 ‘sia}OBIeYD 9914} JO SuBaUI :sajdwes Jo satjiedorg ‘¢ a[quy, CLIO 0+20° LS£0° 010°== S9T0° 610° 8EE0° T+10° +00° = 6S10° +00°== L920" £00°= ‘a's [BAI9}UI ‘Ju0d %66 yysuaT Loe" Sit brs” 889° cOe $8e° 16 Sos 998° C8E" £0S° 959° C8" uboyy £[NPpV cpy [sid ty sf Py b3Npy ¢-3|Dpy c-3INPpV T5pVv OPV e-NPV cANPV TP Py ap, ade\s Sunol ‘WOpaaIf JO daidap Surpuodsaii0d AyyIqeqoid s}I pue ;xX Pa}elnoeo ‘SuOI}eIAap Piepuejs ‘[euUIIOU UL sajnqgi4ysip AOuanbaiy uayM ONeI UoljepNone1 [BAIa}UI aouapIzuoD %86 pue Jysiay puUe YISuUa] JOF S[eAr|}UT Aeg Tyonouel Alenysq TUMOUR YEN Aeg IIOWOVW AI[BIOT + $00°> 86£°9T £ $00°> SOT TE + oso< O+7'S v o0or< Lte9 ‘ad d aX AWB WION L8iT 9£80° LCOUr LEO = 6990" 0c0°=- "ar "S [BAra}UI ‘JU0D %86 OM Er vel © £3e° +6 000° t 0s0°> 6te OF +110 9c 000° + 0s0°> TZt Or O+T0° 90° 000° t 0so< 9£0°S 97C0° 900°=- Se" 90L 000 £6r 8 EZ" 6LT v 0so< c90°6 STTO £00°= tOe 660° + 0s0< 9+0°6 O£TO £00°=+ $8e° 000° + ose< I9L¢ SLT0 $00°=+ Ise 069° fb 964° c $c0' > LLOL 80T0° Ste tIe + 0s0°> $5901 $ct0° L8e° 000° b 0s0'> 989°6 98T0° Lty ubayy “Td d oX “Gas |B AraquUr ural ‘JU0I %66 AVIPBWI0N IYsI9H panurjuos “¢ aq 7, VARIATION LEGUMINOCYTHEREIS ? HODGII 253 Text-figure 2. Three characters considered in this work; total length of valve, height, and obscure reticulation ratio. L: total length of valve, H: height, D. O. R.: dimension of obscure reticulation area at mid-height. Obscure reticulation ratio is given by D. O. R. / L. In all the three regions, the species is prolific on muddy bottoms not much affected by water current and shows an abrupt decline toward areas affected by currents. Therefore, it is impossible to examine the variation of this species in a certain bay, because of the difficulty in obtaining sufficient specimens from different biotopes. METHODS To detect morphological variation, measurement was made on valve length, height, and dimension of obscure reticulation (Text-fig. 2). As already stated, the left valve is more or less larger than the right valve in length and height. This difference is believed to be significant at a very low level, after tests on 38 complete carapaces frem Aomori Bay, using the pair comparison (Simpson, ef a/., 1960) which is a sort of t test for the dif- ference between the means of paired samples. The notation is, | 254 K. IsH1zaK1 where, d = the mean difference between paired measurements, Sd? = variance of these differences, N = number of specimens of either left or right valve. The result are tested at the degree of freedom of (N - 1) and judged as shown in Table 2. Thus the differences of length and height between both valves are significant, and that of obscure reticulation ratio (dimension of obscure reticu- lation / length) is not significant. Moreover, the sexual dimorphism of this species is fairly great, and is commonly the case, the number of male specimens is fewer than that of the female. In spite of an endeavour to prepare samples sufficient for statistical study for each moulting stage from the three regions, specimens younger than adult-3 are very few, and only few valves could be found. With the unfavorable limitations mentioned above, measurement was made on right valves of the female alone, using a binocular microscope equipped with a micrometer scaled 25 microns. The measurements on length, height, obscure reticulation ratio are listed in Table 3. A total of 598 valves was measured, but further consideration will be given to only 492 valves in three moulting stages of the adult-2 to the adult instar. 4mm wo 4 5 6 Te 8mm Text-figure 3. Length-height graph of the sample from Uranouchi Bay. 255 VARIATION LEGUMINOCYTHEREIS ? HODGII WW O'| 6 ‘Alenjsqy twunoueyeN 24} Woz ajduies ay} jo ydeis JYysiay-yJsueT “f IINBIJ-}x9 7, 8 Ae 9g gS va oF 256 K. IsuizakI In general, the discrimination of effects among the regions, and moulting stages may easily be carried out by the two-factor analysis of variance in levels of 3 x 3. This method, however, depends on the samples being the same or nearly so in variance and normal distribution. As shown in Table 3, the results from x’ test show that in nearly half of the samples their frequencies are far from the normal distribution. Therefore, these samples may not be adequate for analysis of variance. Therefore, further consideration was based on the results from the non- parametric method, Mann-Whitney’s u test which has been somewhat revised for lower probability cases. The method is a sort of test by rank of variables and the equation is |U — E(U) |— 0.5 CR = iV iViaren((W)) where U = ning + [m (m + 1)/2] — Ri or mm + [nm (ne + 1)/2] — Re ni: number of specimens in sample 1 no: number of specimens in sample 2 Ri: sum of rank in sample 1 Rs: sum of rank in sample 2 E (U) = nins/ 2, stands for expected value of U when BP Gey a niNe N? —N Wh \Weire (Wi) = Ser (Na) ) ( eee. pa si} , stands for expected variance when p (x = y) = 1/2. INS a Ne f= 2 (te — 4) / 12 t: number of rank in which variables more than 2 referred, i: number of variables in any above case. The results are listed in Table 4. In this work, the datum of significance is taken as 1 per cent. Concerning valve length, significant differences are indicated through the three moulting stages between the samples from Uranouchi Bay and Nakanoumi Estuary, and Uranouchi Bay and Aomori Bay. On the other hand, between the ones from Nakanoumj Estuary and Aomori Bay, differences can be seen in two stages of adult-2 and the adult instar, but not significant in adult-1 stage. As to valve height, significant differences are also indicated between the samples from Uranouchi Bay and Nakanoumi Estuary, and Uranouchi Bay and Aomori Bay through the three moulting stages. Between the ones from Nakanoumi Estuary and Aomori Bay, the difference is significant only in adult- 2 stages, but not in the adult-1 and adult instar stages. Therefore, it can be briefly said that between Uranouchi Bay and the other two regions, there exist significant differences in valve size (length and height); on the other hand, between Nakanoumj Estuary and Aomori Bay, significant difference in valve size seems to be questionable. VARIATION LEGUMINOCYTHEREIS ? HODGII 257 All the specimens in the adult instar stage are ornamented by complete reticulation entirely over the valve surface. Concerning the obscure reticula- tion ratio, significant differences are detected only in the adult-2 and adult-1 stages, between the samples from the Nakanoumi Estuary and Aomori Bay, using the u test. Most specimens from Uranouchi Bay do not have obscure reticulation and show zero obscure reticulation ratio. In this case, the u test is not adequate for such samples because the rank is not in continuity. For- tunately, the frequencies of obscure reticulation ratio of the samples from Aomori Bay show near-normal distribution (Table 3) in the adult-1 and adult-2 stages, when the datum is taken as the probability of 0.05. Therefore, these samples can be judged by their confidence intervals by the following formula, VN sponding to the confidence interval -desired, N: number of specimens in sample. S KEE: ( -t: value of t for N-1 degree of freedom corre- Calculation by this formula indicates their confidence intervals in 98 per cent probability, as 0.314 = 0.020 for adult-1 stage and 0.496 = 0.037 for adult-2 stage. In the confidence interval, the obscure reticulation ratio of the sample of Uranouchi Bay (zero) should be significantly different from those of the other regions. As shown in Plate 1 and Plate 2, the obscure reticulation ratio decreases gradually as maturity is approached except for the samples from Uranouchi Bay where the ratio is nearly zero through all the moulting stages. Such a tendency is also seen from the u test for the samples from the Nakanoumi Estuary and Aomori Bay between adult-1 and adult-2 stages. PROBABLE CAUSE OF VARIATIONS The main ocean current system around Japan, according to Uda (1934), is shown in Text-figure 1. The coastal regions south of central Honshu (Choshi) facing the Pacific are washed by the Kuroshio current and the northern half by the Oyashio current. These currents are said to meet near the central part of Honshu. Thus, a rather sharp boundary can be seen there between the subtropical and temperate faunas (Horikoshi, 1962). On the other hand, no sharp boundary is found along the coast of the Japan Sea side, and the characteristic faunas of the southern areas are found prevailing in more northern areas (Horikoshi, 1962). On the other hand, he suggested that the inner sublittoral zone is, in general, sheltered from the direct main current, and the faunas are distributed widely from Kyushu to Hokkaido. The ostracodes under consideration, in the case of the inner sublittoral zone, are expected to be widely distributed as stated by him. But some characteristic genera as Finmarchinella, Urocythereis, Hemicytheria, and Howeina seem to be restricted to the Japan Sea side. 258 K. IsHizakI The average surface water temperature for each month at the stations near the regions from where ostracodes were collected is shown in Table 1 (Japan Meteor. Agency, 1969, 1970). Esashi, Hiyama County, southwestern Hokkaido is near to Aomori Bay, and its surface water temperature is shown to be lowest among the regions: the lowest average temperature is 4.9°C during February and the highest of 21.3°C during August. Saigo, Okijima, Shimane Prefecture is near to the Nakanoumij Estuary, and its lowest average temperature is 10.8°C during February and highest 27.2°C during August. Ashizuri, Kochi Prefecture is near to Uranouchi Bay, and its surface water temperature is the highest among the regions studied: the lowest average temperature is 16.5°C during February and the highest 27.1°C during August. From the records, there exist, in general, a distinct difference in average water temperature between the three regions throughout the year, except for the summer (August). Among possible environmental factors that are responsible for the varia- tion in valve morphology in these regions, the following three may be con- sidered. 1) The main oceanic current system is thought to have no bearing on the variations of the ostracode valves, because none of the three regions is in the northern half of the Pacific side of Japan where the Oyashio current has direct effects. 2) Even in the inner sublittoral zone, some distinct differences are evi- dent between ostracode faunas of the Pacific side and those of the Japan Sea side. 3) The surface water temperatures are distinct between the three regions, especially during winter. Therefore, it is thought that 2) and 3) cited above may have the most probable bearing on the variation of ostracode morphology. REMARKS From the observations and measurements made on the ostracode samples from Uranouchi Bay, Nakanoumi Estuary, and Aomori Bay, the following re- marks can be made. 1) The valve size is clearly different between the samples of Uranouchi Bay and the Nakanoumi Estuary, and Uranouchi Bay and Acmori Bay. The specimens of Uranouchi Bay are much smaller than those of the other regions. It can not be considered that the valve size depends upon the water temperature where the ostracodes live because no sharp distinction could be found between the specimens of the Nakanoumi Estuary and Aomori Bay. Therefore, the following two working explanations are proposed. a) The first, the variation of the valve size may be due to the tempera- ture above or below a critical point; that is, the valve becomes smaller when the temperature is higher and larger when lower. VARIATION LEGUMINOCYTHEREIS ? HODGII 259 -5 mm oe aS) 6 nif 8 SS) 1.0mm Text-figure 5. Length-height graph of the sample from Aomori Bay. b) The physico-chemical conditions may be fatally distinct for ostracode life between the Pacific side and the Japan Sea side. Judging from the fact that some characteristic ostracode genera are restricted to the Japan Sea side, distinction may be expected, at least, in terms of ostracode zoogeography. At the present, the writer prefers the latter explanation as more suitable for explaining the difference of valve size. 2) The obscure reticulation ratio decreases evidently through ontogeny, in general. 3) The obscure reticulation ratio is significantly different in the three regions. It becomes lower when the ostracode is taken from warm water, and higher from the cold water in the corresponding moulting stages. Thus, it may be that the change of this ratio takes place in correspondence to the gradient of water temperature. K. IsH1zak1 Plate 2 VARIATION LEGUMINOCYTHEREIS ? HODGII 261 PLATE 2 All figures are scanning electron micrographs. Figure 1-5. Serial moulting stages of right valve and normal pore canal of speci- mens from Uranouchi Bay (St. 67 of Ishizaki, 1968), x 93 except for figure 5. 1. Lateral view of specimen of adult-3 stage, ornamented by complete reticulation over valve surface. 2. Lateral view of specimen of adult-2 stage. 3. Lateral view of specimen of adult-1 stage. 4. Lateral view of adult instar. 5. Highly enlarged micrograph of normal pore canal of figure 4. Serial moulting stages of right valves and details of reticulation of specimens from Nakanoumi Estuary (St. 4 of Ishizaki, 1969), * 93 ex- cept for figure 10. 6. Lateral view of specimen of adult-3, obscure reticulation occupying nearly anterior half of valve. 7. Lateral view of specimen of adult-2, slightly obscure reticulation discernible at anterior part of valve. 8. Lateral view of specimen of adult-1, complete reticulation prevailing nearly over entire surface. 9. Lateral view of specimen of adult instar, complete reticulation covering entire surface. 10. Enlarged micrograph of reticulation of the valve of figure 9, flute structure developing down- ward from top of wall of reticulating ridges, *« 1,000. 262 K. IsHizakI REFERENCES Brady, G. S. 1866. On new or imperfectly known species of marine Ostracoda. Zool. Soc., London, Trans., vol. 5, pp. 359-393, pls. 57-62. 1880. Report on the Ostracoda dredged by H. M. 8S. Challenger during the years 1873-1876. Zool., vol. 1, pt. 3, Ostracoda, 184 pp., 44 pls. Horikoshi, M. 1962. Warm temperature region and coastal-water area in the marine biogeography of the shallow sea system around Japanese Islands. Quart. Res., vol. 2, Nos. 2-3, pp. 117-124 (in Japanese with English summary). Japan Meteor. Agency, Tokyo. Japan Meteor. Agency 1969. The results of marine meteorological and oceanographical ob- servations. No. 39, Japan Meteor. Agency, Tokyo, 349 pp. 1970. The results of marine meteorological and oceanographical obser- vations. Ibid., No. 40, 336 pp. Sandberg, P. A., and Plusqueilec, P. L. 1969. Structure and polymorphism of normal pores in cytheracean Ostra- coda (Crustacea). Jour. Paleont., vol. 43, No. 2, pp. 517-521, 12 figs. Simpson, G. G., Roe, Anne, and Lewontin, R. C. 1960. Quantitative zoology. rev. ed., Harcourt, Brace and Co., New York-Burlingame. 440 pp., 64 figs., 5 tables. Sylvester-Bradley, P. C., and Benson, R. H. 1971. Terminology for surface features in ornate ostracodes. Lethaia, vol. 4, No. 3, pp. 249-286, 48 figs. Uda, M. 1934. Hydrographical studies based on simultaneous oceanographical sur- vey made in the Japan Sea. Rec. Ocean. Works, Japan, vol. 6, pp. 19-107, 36 figs., 13 tabs. Kunihiro Ishizaki, Institute of Geology and Paleontology, Faculty of Science, Tohoku University, Sendai, Japan. OSTRACODES CENOMANIENS DU BASSIN DE PARIS: QUELQUES RESULTATS D’ORDRE PALEOECOLOGIQUE ET PALEOGEOGRAPHIQUE RenéE Damotre Centre National de la Recherche Scientifique RESUME Le faunes d’Ostracodes du Cénomanien, récoltées en différentes régions du Bassin de Paris, sont comparées. Certaines faunes déposées dans des milieux similaires, mais provenant de diverses localités, ne sont pas toujours identiques, alors que certaines déposées en milieu différent le sont. L’importance de la localisation géographique des affleurements a |’intérieur d’un méme bassin est mise en évidence. De méme la composition faunistique de certains gisements peut donner des renseignements intéressants concernant la paléogéographie du bassin. ABSTRACT The Cenomanian ostracode fauna collected in different parts of the Paris Basin are compared. Some faunas deposited in same environments, but localised in separate places, are not always identical, then some deposited in different environments are identical. The importance of the geographical posi- tion of the outcrops in a basin is rendered evident. In the same way, the ostra- code association of certain deposits can give some interesting information about the paleogeography of the basin. INTRODUCTION Le Bassin de Paris occupe la plus grande partie du Nord de la France, et mesure environ 580Km du Cotentin a l’Ardenne et 440Km du Boulonnais au Massif Central (Fig. 1). Au point de vue géologique, ce Bassin est constitué de terrains tertiaires et secondaires entourés par des massifs anciens séparés par des seuils. Le centre est occupé par les terrains tertiaires, les terrains secondaires dessinant des auréoles concentriques, mieux visibles dans l’Est du Bassin. Les terrains d’age crétacé inférieur ont une aire d’affleurement trés réduite, située dans |’Est et le Sud-Est du Bassin: Marne, Haute-Marne, Yonne, Aube et un peu au Nord dans le Pays de Bray. Le Cénomanien, qui a été trés transgressif, est visible dans des régions plus étendues : Touraine, Sarthe, Ardenne, Boulonnais ... Dans la région du Mans, région type de |’étage, on peut distinguer dans le Cénomanien des argiles et sables glauconieux (10m environ), les marnes sableuses de Bal- lon, les sables et grés du Mans (40 4 50m d’épaisseur), parfois agglutinés en bancs gréseux a Acanthoceras rothomagense,; les sables du Perche (20 4 30m) souvent agglutinés en blocs ou bancs a Acanthoceras naviculare et par places a trés nombreuses Huitres: Exogyra columba et Ostrea biauriculata. Les dépéts de la Sarthe sont des dépots littoraux, indiquant la proximité du rivage de la mer cénomanienne. Dans |’Aube et l’Yonne, le Cénomanien devient crayeux: craie marneuse a la base, puis craie plus massive et au sommet la craie de Saint-Parres, craie séche en plaquettes. On a ici des dépéts de mer de plate-forme et assez éloignés des zones cotiéres. En Touraine, au Cénomanien se sont déposés des sables glauconieux alter- nant avec des bancs gréseux ou calcaires et surmontés par des marnes.a Ostracées. Comme dans la Sarthe les dép6éts sont littoraux et le rivage de la mer cénomanienne peu éloigné. 264 R. DamoTrTeE mr Ronde — == = “Chatellerault as See Tr Jurassique 5 z Tertiaire Hu crimaire 122 4 KV inferieur superieur CARTE GEOLOGIQUE SCHEMATIQUE DU BASSIN DE PARIS Text-figure 1. Au Turonien et au Sénonien, les dépots se sont effectués dans l’ensemble du Bassin de Paris. PRINCIPAUX GISEMENTS ETUDIES DANS CE TRAVAIL Aube - Yonne: Au Nord de Saint-Florentin (Yonne), environs du Mont Avrelot, le Cénomanien affleure principalement le long de la route départementale 30, en particulier une carriére montre la craie du Cénomanien moyen a Schloen- bachia varians, Acanthoceras mantelli, Inoceramus concentricus. La craie marneuse du Cénomanien inférieur est mieux visible le long de la route départementale 20, un peu a l’Ouest de la carriére précédente. Bairdia pseudoseptentrionalis MERTENS Cytherella ovata (ROEMER) Cytherella parallela (REUSS) Cytherellofdea stricta (J & H.) Cythereis larivourensis D, & G, Cythereis hirsuta D, & G. Cythereis aff. matronae D. &G, Protocythere lapparenti D, & G. Protocythere sp. aff. consobrina TRIEBEL Neocythere vanveeni MERTENS Veenia ballonensis D. & G. Schuleridea jonesiana (BOSQUET) Dolocytheridea bosquetiana (J. et H.) Paracypris sp. Cythereis religata DAM. Cythereis dordoniensis DAM. Cythereis petrocorica DAM. Platycythereis minuita DAM. Platycythereis sp. Protocythere terera DAM. Dolocytheridea crassa DAM. ene vik Whe ve mt i huey awe J; in CENOMANIEN INFERIEUR Saint-Florentin Mont = Avrelot Bairdia pseudoseptentrionalis MERTENS Cytherella ovata (ROEMER) Cytherella parallela (REUSS) Cytherellofdea stricta (J & H.) Cythereis larivourensis D,. &G, Cythereis hirsuta D, & G, Cythereis aff, matronae D, 6G, Protocythere lapparenti D, & G. Protocythere sp. aff. consobrina TRIEBEL Neocythere vanveeni MERTENS Veenia ballonensis D, & G. Schuleridea jonesiana (BOSQUET) Dolocytheridea bosquetiana (J. et H.) Paracypris sp. Cythereis religata DAM. Cythereis dordoniensis DAM. Cythereis petrocorica DAM. Platycythereis minuita DAM. Platycythereis sp. Protocythere terera DAM. Dolocytheridea crassa DAM. Tableau 1 Ballon Saint-Mars-sous=Ballon Boulonnais Petit~Blanc-Nez Région de Chatellerault ++t44 CENOMANION OsTRACODES Paris BASIN 265 Région du Mans: Le Cénomanien inférieur sableux, 4 niveau de minerai de fer n’a pas montré d’Ostracode. Les marnes sableuses de Ballon, au sommet du Cénomanien inférieur, ont été prélevés en particulier a Ballon et a Saint-Mars- sous-Ballon, elles sont trés fossiliféres pour les Ostracodes. Les sables du Perche ne contiennent que trés rarement des Ostracodes (Greez-les-Rocs, Courge- Miatdasees))e Touraine: Les sables glauconieux sont généralement azolques pour les Ostra- codes, quelques prélévements ont montré une faune pauvre (Ciran, Huismes .. ). Les marnes, surtout celles recueillies dans le sondage de Céré-la-Ronde, contiennent une riche et variée faune d’Ostracodes. Dans le Sud de la Touraine (environs de Chatellerault, Vienne) le Cénomanien inférieur est assez rarement fossilifére (Saint-Genest-d’Ambiére). Le Cénomanien moyen par contre ren- ferme de nombreux Ostracodes, en particulier a Noirpuis, Port-de-Piles. Boulonnais: La craie marneuse du Cénomanien inférieur du Petit-Blanc-Nez, et la craie blanche du Cénomanien supérieur du Cran d’Escalles contiennent de nombreux Ostracodes. I] est a signaler que le Boulonnais n’appartient pas au Bassin de Paris selon la, conception stricte du terme, car il est situé au Nord de l’axe de |’Artois; mais les sédiments cénomaniens appartenant a la méme transgression que ceux de l'ensemble du Bassin, ils seront examinés ici. CONTENU FAUNISTIQUE DES DIFFERENTS GISEMENTS ETUDIES I] nous a paru plus simple et plus clair de présenter le contenu faunis- tique des gisements sous forme de tableau par niveau stratigraphique. Des impossibilités matérielles (en particulier des difficultés pour échantillonner a nouveau certains niveaux) nous ont empéché de faire des comptages précis et la notion de fréquence des espéces sera indiquée par les seules notations de rare (— — —) fréquent (+ + +) et abondant (= = = COMPARAISON ENTRE LES FAUNES DES DIFFERENTES REGIONS CENOMANIEN INFERIEUR (TABLEAU 1) L’examen du Tableau 1 montre que la faune est homogéne dans trois régions: Yonne (Saint-Florentin, Mont-Avrelot), Sarthe (Ballon et Saint-Mars- Sous-Ballon) et Boulonnais (Petit-Blanc-Nez). Une seule espéce Veenia bal- lonensis n’a pas été retrouvée dans le Boulonnais, ot par contre Dolocytheridea bosquetiana a été reconnue; deux espéces ne sont pas présentes dans |’Yonne: Cythereis aff. matronae et Protocythere aff. consorbrina. Dans le Sud de la Touraine (environ de Chatellarault) la faune est presque totalement différente au point de vue spécifique, seules trois espéces sont communes a |’ensemble des régions citées ici: Cytherella ovata, Neocythere vanveeni et Cythereis aff. matronac. 266 R. DaMoTTE CENOMANIEN Moyen (TABLEAU 2) Un fait s’impose au premier examen du Tableau 2, il y a une différence trés grande entre le contenu faunistique de la Touraine et celui des autres régions, cette différence se situe au niveau spécifique. Seules trois espéces Cytherella ovata, Cythereis larivourensis et Neocythere vanveeni sont présentes dans l’ensemble des gisements, Bairdia pseudoseptentrionalis est également connu dans presque toutes les régions, excepté le Sud de la Touraine. Les nombreuses espéces qui semblent confiner a la Touraine sont en réalité des espéces connues ou décrites dans le Nord de |’Aquitaine: Dordogne (DA- MOTTE, 1971): Cythereis begudensis, Cythereis dorsospinata, Cythereis reli- gata, Cytherei fournetensis, Cythereis dordoniensis, Cythereis cereensis, Cy- thereis praetexta arta, Cythereis petrocorica, Cythereis sp. 1970, Cytherella dordoniensis, Dolocytheridea crassa, Dordoniella strangulata, Dumontina ceno- mana, Oertliella ingerica, Platycythereis minuita, Parexophthalmocythere oertlit. Pterygocythere rati, Schuleridea tumescens. Certaines de ces espéces sont méme connues en Provence (Sud-Est de la France): en particulier: Cythereis begudensis, Cythereis fournetensis, Parexophthalmocythere oertlit, Pterygocythere rati. REMARQUES D’ORDRE PALEOECOLOGIQUE ET PALEOGEOGRAPHIQUE Le Cénomanien moyen est le niveau le plus intéressant a étudier du point de vue écologie des associations et paléographie du Bassin de Paris. Dans |’Yonne le Cénomanien moyen est crayeux, sédiment qui a du se déposer dans une mer peu profonde, épicontinentale, aux eaux probablement calmes. Les marnes sableuses de Ballon indiqueraient un milieu de dépét littoral, un peu agité, milieu néritique cOotier. Les sables du Perche sont également des dépots de faciés littoraux assez agités. Le milieu de dépot des sables glauconieux de Touraine était similaire a celui des sables du Perche: milieu littoral] assez agité. Les marnes a Ostracées ont dd se déposer dans un milieu plus calme a sédimentation argileuse fine, milieu néritique cétier vraisemblablement. L’ensemble de ces espéces du Cénomanien moyen vivait dans un milieu peu profond, néritique et cdtier, a l’exception peut-étre de ]’Yonne, et elles préfe- raielent un milieu calme, car elles sont moins abondantes dans les sables. Les espéces recueillies dans la craie de |’Yonne, vivaient dans un milieu également peu profond, mais non cotier, milieu plus ouvert (mer de plate-forme). Les milieux de dépot des sédiments cénomaniens moyens de la Sarthe sont de méme type que ceux de la Touraine, et différents de ceux de ]’Yonne or c’est entre l’Yonne et la Sarthe que les similitudes de faune existent. La localisation géographique des gisements sarthois, tourangeaux et de l’Yonne est donc également 4 envisager, car elle peut nous aider 4 comprendre les différences entre les faunes de ces régions. Bairdia pseudoseptentrionalis ( Cytherella ovata (ROEMER) Cytherella parallela (REUSS) Cytherellofdea stricta (J. et F Cythereis larivourensis D & G Cythereis hirsuta D & G Protocythere lapparenti D & G Protocythere aff. consobrina ° Schuleridea jonesiana (BOSQL Neocythere vanveeni MERTE? Cythereis aff. matronae D & ¢ Veenia ballonensis D & G Cythereis sp. 1970 DAM. Cythereis petrocorica DAM. Pterygocythere rati DAM. Cythereis glabrella TRIEBEL Cythereis begundensis BABINC Cythereis dorsopinata DAM. Cythereis religata DAM. Cythereis fournetensis DAM. Cythereis dordonensis DAM. Cythereis cereensis DAM. Cythereis praetexta arta DAM Platycythereis minuita DAM. Parexophtalmocythere oertlii Oertliella ingerica DAM. Dolocytheridea crassa DAM. Dordoniella strangulata APOS’ Schuleridea tumescens DAM. Cytherella dordonensis DAM. Dumontina cenomana DAM. CENOMANIEN MOYEN Saint-Florentin MonteAvrelot Région du Mans Touraine Boulonnais Région de Cran d'Escalles Chatellerault Céré-la-Ronde Bairdia pseudoseptentrionalis (MERT, ) ===== ====+ Cytherella ovata (ROEMER) ====5= Cytherella parallela(REUSS) 9 fwwmnnwme fee Le Cytherellofdea stricta (Up Gis le 6) ) a) eee Cythereis Pe eS a OP ae ee I eee © MD aaau a | Meee Cythereis hirsuta D & G Protocythere lapparenti D & G Protocythere aff. consobrina TRIEBEL Schuleridea jonesiana (BOSQUET) == || wwwemme- dt tt tH nee Neocythere vanveeni MERTENS Cythereis aff. matronae D & G Veenia ballonensis D & G Cythereis sp. 1970 DAM. +++4++ Cythereis petrocorica DAM. Bectiict cast Pterygocythere rati DAM. ft ae eae Cythereis glabrella TRIEBEL Cythereis begundensis BABINOT Cythereis dorsopinata DAM. sla Pl Cythereis religata DAM. se HPeHi rk Cythereis fournetensis DAM. Cythereis dordonensis DAM. bi Ms Cythereis cereensis DAM. ee Cythereis praetexta arta DAM. dso the Platycythereis minuita DAM. bees Parexophtalmocythere oertlii (BAB. ) ood Oertliella ingerica DAM. Dolocytheridea crassa DAM, +++++ EG RS ee eee | | RG hl 8 Schuleridea tumescens DAM, t++t++ Cythere’ Mla dordonensis DAM, Pumontina cenomana DAM. ====: abondant ; + +++ : fréquent ; - - - ~ + fare. Tableau 2 CENOMANION OsTRACODES Paris BASIN 267 Pour les niveaux du Cénomanien moyen de |’Yonne, on a a Ja fois dif- férence de milieu de dépot et éloignement géographique par rapport a la Sarthe et a la Touraine, |’éloignement géographique entre la Sarthe et |’Yonne est méme plus important qu’entre la Sarthe et la Touraine. De ces faits, il se dégage l’idée que l’emplacement géographique des gisements a |’intérieur d’un méme bassin est un facteur a ne pas négliger. La localisation géographique de Ja Touraine explique l’allure particuliére de la faune, il y a eu influence du Bassin Aquitain, avec apport de faune différente plus méridionale, faune de mer plus chaude qui a pu subsister dans la mer tourangelle tempérée par les courants venus du Sud. La communication entre les deux bassins a dt se faire par le détroit du Poitou dés le Cénomanien moyen alors qu’avant cette période les communications entre les deux bassins étaient moins aisées, la mer devant contourner la Vendée et pénétrer en Touraine par la Basse Loire. Toutefois, il ne faut pas oublier que dés le Cénomanien inférieur: la faune des environs de Chatellerault contient quelques espéces connues en Dordogne. CONCLUSION Quand on étudie la paléoécologie de faunes appartenant a un niveau stratigraphique semblable et provenant d’un méme bassin, la localisation géographique des gisements a ]’intérieur du bassin peut influer sur la composi- tion de la faune, le plus souvent par l’intermédiaire d’autres facteurs: clima- tologique en particulier: courants plus chauds amenant des faunes qui peuvent alors subsister dans des eaux plus tempérées que celles de l’ensemble du bassin. A Vinverse la présence de faunes différentes dans un secteur du bassin doit faire penser a la possibilité d’apports extérieurs et donc a la communca- tion avec une autre région. Ici étude de la faune d’Ostracode de la Touraine et de la région de Chatellerault, qui montre de grandes similitudes avec celle du Nord de ]’Aqui- taine, est un argument supplémentaire en faveur de la large ouverture du détroit du Poitou au Cénomanien moyen et méme inférieur. BIBLIOGRAPHIE SOMMAIRE Apostolescu, V. 1955. Un nouveau genre d’Ostracode du Cénomanien de Dordogne: Dor- doniella strangulata n. sp. Cahiers géologiques de Thoiry, No. 33, pp. 329-331. Babinot, J. F. 1970. Nouvelles espéces d’Ostracodes du Cénomanien supérieur de Vauréole septentrionale du Bassin du Beausset (Bouches-du-Rhone- Var). lére partie. Rey. Micropaléont., vol. 13, No. 2, pp. 95-106, 3 pl. 1971. Nouvelles espéeces d’Ostracodes du Cénomanien supérieur de lau- réole septentrionale du Bassin du Beausset (Bouches-du-Rhone- Var). 2 éme partie. Rev. Micropaléont., vol. 13, No. 4, pp. 237- 248, 3 pl. 268 R. DamMoTrTeE Damotte, R. 1971. Quclques Ostracodes du Cénomanien de Dordogne et de Touraine. Rev. Micropaléont., vol. 14, No. 1, pp. 3-20, 3 pl. 1971. Contribution a l'étude des Ostracodes marins dans le Crétacé du Bassin de Paris. Soc. Géol. France, nelle série, t. L, mém. No. 113, 152 pp., 8 pls. Damotte, R.. et Grosdidier, G. 1963. Quelques Ostracodes du Crétacé de la Champagne Humide. 1 Albien-Cénomanien, Rev. Micropaléont., v. 6, No. 1, pp. 51-66, 3 pls. Deroo, G. 1956. Etudes critiques au sujet des Ostracodes marins du Crétacé in- férieur et moyen de la Champagne Humide et du Bas-Boulonnais. Rey. l’Inst. Fr. Pétrole, vol. XI, No. 12, pp. 1499-1635, 5 pls. Howe, H. V., et Laurencich, L. 1958. Introduction to the study of Cretaceous Ostracoda. Louisiana State University Press. 536 pp. Juignet, P. 1971. Modalités du controle de la sédimentation sur la marge armoricaine du Bassin de Paris a lAptien-Albien-Cénomanien. Bull. Bureau Recherches Géologiques et Miniéres, 2éme série, section I, No. 3, pp. 113-126. Moore, R. C. 1961. Treatise on Invertebrate paleontology, part. Q. Anthropoda 3. Crustacea Ostracoda. Geol. Soc. America and Univ. Kansas Press, 442 pp. Morkhoven, F. P. C. M. van 1962-1963. Post Paleozoic Ostracoda, Elsevier Publishing Company, vol. I, 204 pp., vol. II, 478 pp. Oertli, H. J. 1963. Faunes d'Ostracodes du Mézozoique de France. E. J. Brill éd. — Leiden, 57 pp., XC pls. Pokorny, V. 1964. Some palaecological problems in marine ostracode faunas, demon- strated on the Upper Cretaceous ostracodes of Bohemia, Czechor slovakia, Publ. staz. zool. Napoli, 33, suppl., pp. 462-479. Pourmotamed-Lachtenechai, F. 1971. Etude micropaléontologique du Cénomanien dans le Nord du Seuil du Poitou. Thése 3éme cycle, Université Paris, 195 pp., 19 pls. ronéotypé, inédit. Renée Damotte, Centre National de la Recherche Scientifique, Laboratoire de Micropaléontologie, Université de Paris VI. Tour 15-E4, 4 Place Jussieu 75 - Paris V - France DISCUSSION Dr. H. J. Oertli: Did you have an opportunity to see in greater detail forms of southeastern France and compare them with your Touraine forms? It is also important to demonstrate that Touraine, which is in the southwestern part of the Paris Basin, has common species with the Aquitaine, which are 100% different from the Paris Basin. CENOMANION OsTRACODES Paris BASIN 269 Dr. Damotte. On the first slide (map in the text) you can see the position of Touraine in the Paris Basin, and just on the south of “détroit du Poitou” is the North of Aquitaine, the Dordogne. I know myself the fauna of Dordogne, north of Aquitaine, and I have studied some samples of the Pyrénées and I have seen the same species. Dr. Babinot is working on the Provence fauna, and he found some of my species. We have discussed those problems and he has seen my fauna of Touraine. Dr. Oertli: We have two biogeographical Cretaceous provinces, a northern part and a southern part, both very well delimited. Dr. A. Liebau: Could you remark on the lagoonal ostracodes in the Cenoman- ian. Dr. Damotte: Yes, but here I speak only of the marine fauna. I know the existence of lagoonal faunal in the Cenomanian, but it is not the subject of this work. Dr. F. M. Swain: In the middle Atlantic region we have a lagoonal Cenoman- ian sulcate cytherideid that we (Swain and Brown, 1964) named Fossocytheri- dea. | wonder if either in France or elsewhere you are familiar with, there are any sulcate cytherideids? Dr. Damotte: I have never seen such a type of form. Dr. Oertli: But I think there is a lot still to be done with the Cenomanian. In every new sample you find new things. It is a new world that is arising with the Cenomanian. Dr. Damotte: We have in all Cenomanian samples a lot of species, and especially some new species and genera, so I want to continue the study of this fauna. Dr. Liebau: Perhaps it is of interest to you that in the Cenomanian of the Ile Madame (Charente Maritime) and of Roquefort (Landes) species of the Provence fauna occur (as described by Babinot). Very typical is a Cythereis species and the “Opimocythere” taxyae-group. These faunas represent a more lagoonal facies. Dr. Damotte: Yes, but it is marine,... Dr. Liebau: It should be noted that in these lagoonal Cenomanian faunas the oldest known hemicytherids appear — but this depends also on the definition of this family. ed Oe a am has okt ‘yl bation s : Are om, yore oe I chdatenphaiattoft: fir hs . te pale Adcom cage ATE Miia ‘ ¥ ere 7 x =merierny haprwl Riek ¥ nih. Tig co ; aed recs bog 4 4 ‘aa om, tly p MAO NAAE c.> ie 5 a Ye \e yy be = pe. Laas oy oi e wf! "v4 e fell ay C my nya THE PALAEOBIOLOGY OF SOME UPPER PALAEOGENE FRESH-WATER OSTRACODES M. C. KEEN University of Glasgow ABSTRACT Two assemblages can be recognised amongst the fresh-water ostracodes of the upper Eocene and Oligocene of western Europe. These are the Candona- Cypridopsis Assemblage and the Moenocypris Assemblage. The first of these is the more complex and the more widely distributed. It is thought to have characterised lake margins and shallow lakes up to about one metre in depth; a distinct subassemblage is found in limestones, with a striated cyprid of the Eucypris tenuistrata (Dollfus) group and Cyfridopsis spp. The Moenocypris Assemblage, absent in the Paris Basin, is thought to have characterised deeper waters. The mode of life of the various species is discussed. RESUME On a décrit deux associations fauniques d’ostracodes d’eau douce de l’Eocéne supérieur et de l’Oligocéne inférieur en Europe de l’ouest, a savoir l'ensemble Candona-Cypridopsis et Vensemble Moenocypris. La premiére as- sociation se compose de nombreuses espéces, et on l’a reconnu en Angleterre, dans le bassin de Paris, en Alsace, dans le bassin de Mayence, et en Hesse. Une sous-association coincide avee les roches calcaires; elle est representée par un Cyprididae strié et Cypridopsis. On a reconnu la deuxiéme association en Angleterre et dans le basin de Mayence; elle se caractérise par le seule genre Moenocypris. Divers critéres suggérent que |’ensemble Candona-Cypridop- sis temoigne un milieu prés de la céte du lac ou un milieu d’eau peu profonde (1m.?); l'ensemble Moenocypris témoigne un milieu plus profonde (2-10m.?). INTRODUCTION The Palaeogene deposits of western Europe contain many fresh-water hori- zons; this report however, is only concerned with the upper Eocene and lower Oligocene. In southern England the horizons dealt with are the lower and upper Headon Beds, Osborne Beds, Bembridge Limestone, and the Hamstead Beds. Some authors regard the whole of this successicn as Oligocene (e.g. Curry, 1966), while others would place the base of the Oligocene at the base of the Hamstead Beds (e.g. Cavelier, 1969; Keen, 1972). In the Paris Basin samples have been examined from the Eocene Calcaire de Nogent l’Artaud and the marls underlying the Marnes 4 P. /udensis at Verzy, and from the Olige- cene Bande blanche and Calcaire de Brie. Few fresh-water ostracodes have been obtained from Belgian samples. Farther eastwards lower Oligocene fresh- water ostracodes are found in the Couches de Pechelbronn of Alsace and the Mainz Basin, and the Melanienton of Hesse. The taxonomy of the ostracodes is far from satisfactory. Many species still need describing, and some of the commoner of these are known almost entirely from juvenile moult stages. Generic designation is not always easy, while geographical variation and distribution present difficult problems. None- theless, a great deal of work has been carried out in recent years: Stchepinsky (1960), Margerie (1961, 1972), Triebel (1963), Haskins (1968), Carbonnel and Ritzkowski (1969), and Keen (1972). 272 M. C. KEEN FRESH-WATER OSTRACODE ASSEMBLAGES Those samples which yielded ostracodes were divided into two main groups for statistical purposes, and for each group Jaccard’s Coefficient of Correlation was calculated for those species occurring in four or more samples. The first group, consisting of 32 samples, was from the Headon, Osborne, and Bembridge Beds of the Hampshire Basin; the second, of 22 samples, was from the Hamstead Beds of the Isle of Wight, and the Sannoisian of the Paris Basin. The separation was necessary because two distinct units are present, with different, although often related, species. The combination of the English and French Sannoisian samples is justified because the fauna is so similar on the species level that the absence of a particular species from one of the areas is itself of importance. Other French localities were not included because they yield different species, while there were not enough samples to warrant statistical treatment. Two distinct faunal assemblages can be recognised (Text- fig. 1, 2; Table 1). These have been discussed briefly in Keen (1972), and it should be noted that Vecticypris packsoni Keen is now included in a different assemblage. The assemblages can also be related to sediment-type and to macrofauna. THe CANpDoNas-CypriDopsis ASSEMBLAGE This is the more complex of the two. Associated gastropods are Galba and Planorbina; Chara nucules are extremely abundant; seeds of water plants are often present. The sedimentary rock may be a green, black, grey, or chocolate- coloured clay, or a buff-coloured limestone with algal “pisolites” and algal laminations. Certain species are more commonly found in the limestones, and these form a subassemblage. The common members of this subassemblage were tested by means of an X®2 test to see if their association with limestones was significant. The following values of ~ were obtained: Earcy pris) CLateruUisiniata, -= ee 0.001 Gandonarsp; Bahia s. oe ee 0.005 Gapnidopsismuulvo laa 0.03 These are all highly significant statistically, well above the 5% level usually applied by modern ecologists. It should be borne in mind however, that the number of samples available for testing was low, 9 limestones and 23 non-lime- stones. Nevertheless, when the X’* test was applied to Candona sp. A, ~p was found to be 0.40, indicating a lack of any clear relationship with limestones. To complete the picture, # for Moenocypris was found to be —0.08, indicating some significance in its absence from limestones. Tue Moenocypris ASSEMBLAGE This is much the simpler of the two, Moenocypris often comprising the whole of the sample. Associated molluscs are the gastropods Melanopsis and Viviparus, with the bivalve Unio; abundant seeds and leaves of waterplants such as Stratiotes and waterlilies are often present. The enclosing sedimentary rock is usually a grey silty clay, occasionally a fine-grained sandstone. 273 PALAEOGENE FRESH-WATER OsTRACODES “UOVEITIOD FO WorLIFZa0 S,presef fo wieIseIp UoNeE[[a}suoD *] a1NBy-3x9,7, D}olsysinua}y sisdXkong ds puopun | Ba0o) ,GuVoovi Isaquoy sisdk20ua0w NVISIONNVS ‘dds stidk.0ua0pw psoqing sisdopisdd> Sd3¢@ S9OCINaW3E 8 “ANYOESO ‘NOGVSH JOVIEWASSY SlddAD0UBz0=-= ; AOVIGWASSY sisdopisidk>—puopun> M. C. Keen 274 ‘saBe[qUIASSE apPOdeI}SO Ia}EM-YSAIFZ 9Y} JO S}eIqey paysasBng *Z 9iNBIf-}x9 7 : ‘UOl}D]NIAID 1OOd '412}DM ]]!}S ‘SJUZWIPZS WO}}OG Ul YF 2A1}DHaN ‘Hd 2uljDyIVv ‘pnw eee JO SD2JID BB S}UD|d pabsawqns UyIM \ ‘orup) ‘sisdounjaw ‘SNIDAIAI A anv ligdsiagad | eval ) DG SISdOdIlddAD eo ea < SIYdADONIOW yds YNOGNV q'ds VNOGNYD 42}DM Hulaow AyMo]s JO JS "UF 2Al}ISOd ‘(8~) Hd 2ulDyxIlv ‘DADYD'S}DW ]DH]D 'S2l]!]42}DM 'SP221 YIM ‘Dulqsoubjqg ‘PgqjOS J¥V1 MOTIVHS YO 3904 J3yVI bis aH A =o SYSMOUUNE 3 SUaTASaMmMa ' ' t ' 1 1 ! ' t ' ' ' ' ' ' ‘ 1 VINdAD SladADNA SY3T1SMd LNV Id WOLLOG 8B SYAWWIMS Candona (Pseudocandona) sp. A B Candona (Pseudocandona) sp. B B Cypridopsis bulbosa (Haskins, 1968) S Cypridopsis sp. A Eucypris cf. tenuistriata (Dollfus, 1877) S Hemicyprideis montosa (Jones & Sherborn, 1889) Cypria sp. A S B S PALAEOGENE FRESH-WATER OSTRACODES 275 Table 1. Species found in the Candona-Cypridopsis Assemblage OLIGOCENE Candona (Pseudocandona) sp. Cypridopsis soyeri (Margerie, 1961) Eucypris tenuistriata (Dollfus, 1877) Ilyocypris boehli Triebel, 1942 ***Vecticypris jacksoni Keen, 1972 ***Cypria sp. ***Darwinula sp. **"*Herpetocypris nuda (Dollfus, 1877) Strandesia cf. spinosa Stchepinsky, 1960 ****Tineocypris sp. *Limestone sub-assemblage **Bembridge Limestone only **England only B Bottom dwelling forms **Paris Basin only S Swimmers ENVIRONMENTS AND PALAEOBIOLOGY The environment envisaged for the Candona-Cypridopsis Assemblage is a shallow lake or lake edge, less than a metre deep and perhaps often emer- gent. Reeds, rooted water plants, Chara, and algal mats would have grown in the shallow water (Text-figs. 2). For a more detailed discussion see Daley (1972) and Edwards (1967). Galba and Planorbina are usually found in water less than 2 metres deep and are capable of living out of water and breathing air (Daley, 1972). In the following discussion of the ostracodes, especially their mode of life, much use has been made of Sars (1928). Candona (Pseudo- candona) spp. probably burrowed or crawled slowly over the soft bottom sediment as do their modern descendants: Candona (Pseudocandona) sp. B where algal lime was accumulating, Candona (Pseudocandona) sp. A not being restricted by the type of bottom sediment. The Eucypris tenuistriata group of ostracodes probably lived and swam amongst the waterplants but was re- stricted to areas of carbonate sedimentation. This may reflect a primary control by sediment, the ostracodes living near the bottom in search of food, or a secondary control via the plants. Recent species of Eucypris seem to live near the bottom, so the first of the two suggestions may be the more probable. Cypridopsis spp. probably swam amongst the waterplants: this is suggested by comparison with living species of the genus, most of which are active swim- mers; by its morphology, with rounded anterior and ventral margins (Hart- mann, 1965, and Benson in discussion of Hartmann, 1965) ; and by their greater distribution than other members of the assemblage. Cyfria is another active swimmer generally found in shallow water. Going into deeper water (2-10 metres ?), the Moenocypris Assemblage would have been found. The vegetation would have consisted of submerged waterplants, drifted and partially rotted shore plants, with areas of bare lake muds. Melanopsis and Viviparus browse over bare areas, Viviparus usually DmWWnntnnowd 276 M. C. Keen being abundant where the vegetation is abundant (Daley, 1972). Although Mocnocypris is an extinct genus, there are several reasons for believing it to have been a freshwater bottom crawler. It is a member of the Cyprididae, most of which inhabit freshwater, is found associated with typical fresh- water molluscs, and when found with other ostracodes these are fresh-water genera. Its elongate shape is rare for active swimmers; its numerous and well- developed ventral radial pore canals are characteristic of bottom dwelling crawlers (Hartmann, 1965); and finally its central muscle scars are situated well to the anterior, perhaps indicating poorly developed antennae for swim- ming, but well-developed posterior appendages for crawling. Ilyocypris ap- peared in the Oligocene and obviously had a broader environmental tolerance than the other ostracodes. Thus it is found in both assemblages and is the only ostracode to have a significant relationship with Moenocypris (Text-fig. 2). It Was presumably a swimmer, and it is interesting to see that its closest associa- tion is with Cypridopsis soyeri, another swimmer. However, unlike Cypridopsis it was not apparently affected by the depth of water, giving it a wider range. None the less, it is more closely associated with the Candona-Cypridopsis As- semblage so presumably was more abundant in the shallower waters. Recent species of I/yocypris are not amongst the most active of the swimming ostra- codes, mainly living on the bottom. It is likely that the Oligocene species lived similarly, its swimming power allowing its wide distribution. Vecticypris also appeared in the Oligocene; its rounded shape suggests a swimmer, with a range similar to Cypridopsis spp. Hemicyprideis montosa has been regarded as a euryhaline ostracode, sometimes present as part of the biocoenosis of the Candona-Cypridopsis Assemblage (Keen 1971). Its main distribution, however, was in mesohaline salinities. The two fresh-water assemblages may have inhabited separate areas, or may have been found in a single lake. Certainly there is very little mixing of the two; an exception can be seen in BC 76, Text-figure 3 (and see below). The physical conditions envisaged are indicated on Text-figure 2. The water must have been alkaline as evidenced by the molluscan faunas. The presence of well-preserved leaves and rootlets in the sediments of the Moenocypris Assemblage indicates the existence at times of a reducing environment, at least within the sediment if not the bottom waters. The water could only have flowed slowly, if at all, because of the presence of a well-preserved ostracode fauna. This is supported by the types of sediment and the fact that the fragile molluscan shells are usually complete. Salinity must have been less than 3%o in most cases, again evidenced by the fauna. However the fresh-water environ- ment graded into lagoonal regions with higher salinities, giving distinct ostra- code faunal assemblages. Cytheromorpha bulla Waskins inhabited waters thought to have had a salinity of 5-9%o and this ostracode may be present within either of the fresh-water assemblages. However, any rise in salinity much above 3%o0 would have killed off the molluscs (Daley, 1972). The temper- ature is difficult to determine from the ostracodes; evidence from the other fauna and flora, presence of gypsum deposits and laterites, suggest much Warmer conditions than today. The climate has traditionally been regarded as subtropical to warm temperate. Candona sp.A or Candona sp. Candona sp.B or Ilyocypris boehli Cypridopsis bulbosa or Cypridopsis soyeri Cypridopsis sp.A or Vecticypris jacksoni Eucypris cf. tenuistriata or E.tenuistriata Cypria sp.A o Eucypris amygdala Cypris sp. or Darwinula sp. Moenocy pris Hemicyprideis montosa . Herpetocypris nuda Cytheromorpha sp. Text-figure 3. Diagram to show the percentages of various species in selected examples. HH 21, lower Headon Beds, Headon Hill; HH 53, upper Headon Beds, Headon Hill; CB 12, upper Headon Beds, Colwell Bay; MF 3, lower Headon Beds, Milford; BC 76 and BC 98, middle Hamstead Beds, Bouldnor Cliff; CM 17, Bande blanche, Cormeilles-en-Parisis. In the key some symbols have two meanings; the first refers to the four Eocene samples on the left hand side of the diagram, the second to the three Oligocene samples on the right. N = number of specimens. 278 M. C. Keen GEOGRAPHICAL AND STRATIGRAPHICAL DISTRIBUTIONS In general terms the Candona-Cypridopsis Assemblage is characteristic of the lower and upper Headon Beds, Bembridge Limestone, and a few horizons within the middle Hamstead Beds; while the Moenocypris Assemblage charac- terises the upper Headon, Osborne, and middle Hamstead Beds, although it also occurs in the lower Headon Unio Bed of Milford. The Moenocypris Assemblage is absent in the Paris Basin. The reason for this is fairly self evident: all the fresh-water deposits which have yielded ostracodes are lime- stones. Thus, as would be expected, the Candona-Cypridopsis Assemblage is often dominated by striated cyprids of the Eucypris tenuistriata group. In the Calcaire de Nogent l’Artaud of Nogent |l’Artaud, Rosiéres and Grisy-les- Platres it is represented by E. grisiensis Margerie (Margerie, 1972); in the marls underlying the Marnes a P. /udensis by a closely related form, accom- panied by two undescribed species of Cypridopsis and rare Candona (Pseudo- candona). The fauna of the Bande blanche can be seen in Text-fig. 3, C.M 17. In Alsace the Couches de Pechelbronn have yielded many examples of the Candona-Cypridopsis Assemblage. A sample collected from the type locality yielded: Eucypris pechelbronnensis Stchepinsky (30%; cf. E. amygdala of the Bande blanche), Candona (Pseudocandona) fertilis fertilis 'Triebel (22%), Herpetocypris sp. 1 Stchepinsky (22%; cf. H. nuda of the Bande blanche), Cypridopsis entzheimensis (Stchepinsky) (17%), and Ilyocypris sp. (9%). This was from a clay, so the absence of the striated cyprid is not unexpected; otherwise it is very similar in composition to the fauna of the Bande blanche. The Couches de Pechelbronn of the Mainz Basin have yielded both as- semblages; Cypridopsis appears to be rare, while the striated cyprid is absent. Once again, only clays are present. The Moenocypris Assemblage is also found in the middle and upper Oligocene and in the Miocene (Triebel, 1963). In Hesse, only the Candona-Cypridepsis Assemblage is present, with several species of Cypridopsis, Candona (Pseudocandona), Strandesia, Ilyocypris, and the striated cyprid E. tenuistriata straubi (Carbonnel and Ritzkowski), (Carbonnel and Ritzkowski, 1969). POPULATION STRUCTURE The percentages of the different species are indicated in seven selected samples in Text-fig. 3. The first thing to notice is that the size of the samples is small. Jaccard’s Coefficient depends upon the presence or absence of a species in a sample, so it is important that all the species present are recorded. Normally some 300 specimens are needed to satisfy this requirement. Such numbers were impossible to obtain from the size of the samples collected. Fresh- water ostracodes are not often abundant, and a great deal of sediment was searched to obtain the present number of specimens. However, as the number of species is small it is likely that a smaller number of specimens is needed PALAEOGENE FRESH-WATER OsTRACODES 279 to give a complete faunal analysis, while only the commoner species were used to determine the assemblages. HH 21 and BC 98 show typical clay assemblages, dominated by Candona (Pseudocandona), and with Cytheromorpha bulla as thanatocoenosis in HH 21. A typical limestone assemblage can be seen in CB 12; note that although Candona (Pseudocandona) sp. B is characteristic of limestones, Candona (Pseudocandona) sp. A is still the more abundant of the two. Some limestones could almost be called Cyfridopsis limestones (HH 53); in these the ostracods can be seen clearly in the rock, with complete carapaces, although the valves are usually separated during preparation. CM 17 is from the Bande blanche; note the large percentage of H. montosa. In the three Oligocene samples il- lustrated (BC 76, BC 98, CM 17) Ilyocypris boehli forms an approximately constant percentage of the fauna, although the other constituents vary. BC 76 is one of the few samples to show a mixture of the two assemblages; this may be due to deepening, or shallowing, of the lake, resulting in one of the assem- blages forming a remanié portion of the sample. MF 3 illustrates a Moeno- cypris Assemblage, with small numbers of C. bulbosa; in fact Candona (Pseu- docandona) spp., E. tenuistriata, and Darwinula are also occasionally found with Moenocypris. This is presumably due to postmortem transportation. Moenocypris, being a large ostracode, can often be seen in hand specimens, and in the middle Hamstead beds sometimes completely covers bedding planes. Sexual dimorphism is not readily apparent in many of the species. Margerie (1972) reported it in E. grisiensis. Males and females have been recognised in all the Moenocypris species and in E. cf. grisiensis due to the preservation of the imprints of testes and oves, but it is impossible to deter- mine their relative abundance. The age structure differs from species to species. The most “normal” of the species delt with are those of the E. tenuistriata group. Adults and larval stages are usually preserved, and in several samples many different moult stages can be recognised. The samples from Verzy have yielded several hundred specimens, making it possible to differentiate seven moult stages. The latter are not clearly differentiated so it is possible that EF. cf. grisiensis had more than one breeding season per year (Keen, 1972). In the case of the Cypridopsis larval stages are rare, while with Candona (Pseudocandona) spp. only 2-3% of the specimens are adult. The small size of Cyfridopsis (.4-.5 mm) may have led to the easy destruction of the even smaller larval stages. The lack of adults is more difficult to explain. It may be preservational, the larger adults being more liable to break; it may be an effect of migration; or it may reflect the true population structure, with few individuals reaching maturity. If the latter is the case then some environmental factor must have been operating, but it is difficult to determine what this may have been. SOME TAXONOMIC COMMENTS Haskins (1968) has described and figured some of the species referred to. Candona (Pseudocandona) sp. A = Potamocypris sp.; Candona (Pseudo- 280 M. C. Keen candona) sp. B = ?Candonopsis sp., the striated cyprid is referred to as 2Scottia sp.; Cyclocypris bulbosa Haskins has been placed in the genus Cyfri- dopsis, and Candona forbesii Jones into Moenocypris. The generic designation of the striated cyprid is problematical; for a discussion see Margerie (1972). For reasons of uniformity Margerie’s con- clusion, 7. e. that Eucypris is the nearest genus, has been adopted, although such a designation is stil] debatable. REFERENCES Carbonnel, G., and Ritzkowski, S. 1969. Ostracodes lacustres de l’Oligocéne. Arch. Sci. Genéve, vol. 22, pp. pp. 55-82, pls. 1-5. Cavelier, C. 1969. La limite ‘Eocéne-Oligocéne’ In Colloque sur ’lEocéne, Paris, 1968, vol. 3, Mém. Bur. Rech. géol. min., No. 69, pp. 431-437. Curry, D. 1966. Problems of correlation in the Anglo-Paris-Belgian Basin. Proc. Geol. Ass., vol. 77, pp. 437-467. Daley, B. 1972. Macroinvertebrate assemblages from the Bembridge Marls (Oligo- cene) of the Isle of Wight, England, and their environmental sig- nificance. Palaeogeography, Palaeoclimatol., Palaeoecol., vol. 11, pp. 11-32. Edwards, N. 1967. Oligocene studies in the Hampshire Basin. Thesis, University of Reading, pp. 170, unpublished. Hartmann, G. 1965. The problem of polyphyletic characters in ostracods and its sig- nificance to ecology and systematics. Pubbl. Staz. zool. Napoli, vol. 33 suppl., pp. 32-44. Haskins, C. W. 1968. Tertiary Ostracoda from the Isle of Wight and Barton, Hampshire, England, Part II. Rev. Micropaléont., vol. 11, pp. 3-12, 2 pls. Keen, M. C. 1971. A palacoecological study of the ostracod Hemicypridets montosa (Jones and Sherborn) from the Sannoisian of North-West Europe. Bull. Cent. Rech. Pau, S.N.P.A., vol. 5 suppl., pp. 523-543, 2 pls. 1972. The Sannoisian and some other Upper Palaeogene Ostracoda from North-West Europe. Palaeontology, vol. 15, pp. 267-325, pls. 45-56. Margerie, P. 1961. Ostracodes de la carriére Lambert a Cormeilles-en-Parisis. Bull. Soc. amic. Géol. amateurs, No. 2021, p. 1-24, 4 pls. 1972. Essai de “quantification’ ’du contour des ostracodes a loccasion de la description d’une nouvelle espéece de Cypridinae du Marine- sien du Bassin de Paris. Rev. Micropaléont., vol. 14, pp. 227-234, 1 pl. Sars, G. O. 1922-1928. An account of the Crustacea of Norway. Bergen Museum, vol. 9, 277 pp. Stchepinsky, A. 1960. Etude des ostracodes du Sannoisian de l’Alsace. Bull. Serv. Carte géol. Alsace Lorraine, vol. 13, pp. 11-33, 3 pls. PALAEOGENE FRESH-WATER OsTRACODES 281 Triebel, E. ; ' 1963. Ostracoden aus dem Sannois und jungeren Schichten des Mainzer Beckens: 1, Cyprididae. Senckenberg Leth., vol. 44, pp. 157-207, 12 pls. M. C. Keen, University of Glasgow, Glasgow W2, United Kingdom. DISCUSSION Dr. L. D. Delorme: Where you find J/lyocypris, is there any indication of water movement, either a stream entering the lake close by or current move- ment? Dr. Keen: There is no evidence of water movement from the sediments con- taining the ostracodes, so they were probably deposited in fairly still water in flood plain lakes. Small scale current bedding and channeling occur within the succession, but such horizons are devoid of ostracodes. Dr. H. S. Puri: You referred in your paper to “deeper” and “shallower” and a “hot” lake. I would like to ask what were depths and temperature ranges in the lakes? Dr. Keen: As regards temperature, the ostracodes offer little information. From other evidence these Tertiary deposits are certainly subtropical, perhaps even tropical, so we are dealing with warm water. I wouldn’t like to go any further than that. As for the deep water ws. shallow, I hesitate to give any exact figures. For shallow I am thinking of something in the order of a metre or less, for deep around four or five metres. There could thus be two situa- tions, one where a single lake has these two depth zones, the other where there are extensive areas of shallow lakes. Dr. A. Liebau: You mentioned the gastropod Melanopsis as characterizing your fossil freshwater faunas. As far as I know, Melanopsis indicates brackish water influences. In Upper Cretaceous faunas I have studied, Melanopsis is found from about polyhaline down to oligohaline brackish water. Also the Recent representatives I know live next to the sea (Spain, Morocco) or in the neighbourhood of a salt lake (Tunisia) or get e.g. salinity from Miocene gypsum (Spain: Rio Genil). Dr. Liebau: I cannot imagine that Melanopsis lives in true fresh water. But on the other hand besides Viviparus, another genus in your list, also Unio is said to indicate a salinity less than 3%o (at least in the Baltic Sea area). Perhaps there were some salinity influences below the 3-per mille mark. I mention this because also such a small difference could be important for the occurrence of some fresh-water ostracodes. Dr. Keen: Melanopsis is one of those gastropods that inhabits both brack- ish and freshwater. I wouldn’t draw any firm conclusions from its occurrence, although it is very common. I draw my evidence from Vivifarus which is never found in salanities greater than 3%o at the present day. (i). By freshwater, I mean less than 3%0, although I believe it to have been less than 0.5%o in most cases. Unio is also present, and, as you mention, provides further evidence for freshwater conditions. 282 M. C. Keen (ii). May I refer you to Daley (1972)? In his discussion of the habitat of Melanopsis from the Bembridge Beds, he mentioned its problematical signifi- cance with regard to salinity, concluding that while it inhabited freshwater together with Vivifarus, it may have had a higher salinity tolerance than the latter, as it also occurs in shell concentrates thought to have accumulated in waters transitional from fresh to brackish. Dr. R. L. Kaesler: Is it possible that the Moenocypris “assemblage” is from the hypolimnion and that the other, more diverse assemblage is epilimnetic? Dr. Keen: I don’t believe these terms are applicable to the kind of lake I’m envisaging. Firstly, they were probably subtropical, and secondly they were probably never really deep (i.e. > 20m.). So I doubt if there was any marked temperature division. It is more likely that Moenocypris would have been found in the lower infralittoral zone (i.e., zone of submerged water plants), while the Candona-Cypridopsis Assemblage would have been found in the upper infralittoral zone (i.e. zone of emergent water plants). Dr. Sohn: Meclanopsis is shallow in the Jordan River, Israel. The striated form looks something like Zonocypris. Dr. Keen: As I’ve already mentioned, I have not placed much emphasis on Melanopsis. The striated ostracode certainly resembles Zonocyfris, and in fact I first assigned it to this genus. The ornamentation is different, however, being longitudinal rather than concentric as in Zonocypris. Dr. Oertli: We find similar striated forms as far down as Lias. Several other striated species still not described occur also in the Spanish Wealden. Dr. Keen: (i). I hadn’t realised that. Do these show the same smooth and striated forms? (ii). The taxonomic position of these forms is difficult. Their outstanding characters, 7.¢. striations, appears to be ecologically controlled. According to Dr. Carbonnel temperature may be the controlling factor. So you can hardly define a group upon a phenotypic character. And yet, they do seem to form a distinct group of ostracodes. Dr. Swain: With regard to the depth of the lakes, the assemblages that you cited composing mostly snails and ostracodes suggest epilimnetic conditions rather than hypolimnetic, perhaps shallower vs deeper parts of the epilimnion. We have a form similar to the striated ostracode in the Green River Forma- tion, and I have the types here if you would care to look at them. Dr. Keen: What genus do you refer it to? Dr. Swain: I called it a Metacypris, but it probably is not. Dr. Hazel: I am curious about how many specimens per sample and how big a sample do you have to take? Dr. Keen: This varies a lot. Some of the limestones are very rich in ostracodes, in fact some could almost be called ostracode limestones. On the other hand, with some samples, you need to sort through several pounds of sediment to find 30 or so specimens. Thus the numbers vary considerably. Some idea of the numbers is given in the text, and in Text-figure 3. Dr. Sohn: Is Jlyocypris a swimmer or a crawler? PALAEOGENE FRESH-WATER OsTRACODES 283 Dr. Keen: According to Sars some species are swimmers, some are pre- dominantly crawlers. Dr. Hartmann: The striated form (?Eucypris) may equal Strandesia, and the Moenocypris may equal Stenocypris. Strandesia and Stenocypris are warm water forms. All the species are probably calm water forms. Dr. Keen: I’m not too sure whether this is meant as a taxonomical or ecologi- cal synonymy. I wouldn’t agree with assigning them to these genera. Ecologi- cally, I don’t know about Strandesia, except that its a warm water form; Moenocypris is envisaged as having a similar life mode to Stenocypris. ied gis " Division ° ‘ tines re as ro a hy Ase ri peg ; LemAitios’ reid = yin cei 5 2 ae lig larday Ri LE FACTEUR LISSE CHEZ CERTAINS OSTRACODES TERTIAIRES: UN INDEX DE PALEOTEMPERATURE G. CARBONNEL Université Lyon1-Claude Bernard RESUME La disparition de l’ornementation, ou facteur lisse, et ses modalités sont étudiées chez plusieurs espéces marines telles Leptocythere pentagonalis Car- bonnel et Elofsonella amberii Carbonnel ou saumatres Cytheromorpha sp. Kus- ter-Wendenburg et Hemicypridcis dacica grekoffi Carbonnel, enfin lacustres telles Eucypris? grisiensis Margerie, Eucypiis? tenuistriata straubi Carbonnel, Ritzkowski et Limnocythere n. sp. L’observation au microscope électronique a balayage a permis la découverte de nouvelles structures anatomiques exclusives des formes lisses, a savoir verrucae et aréa-polyporée. Leur signification physiologique est encore incon- nue. La corrélation entre le facteur lisse et ]’apparition de tubercules a conduit a la définition des morphotypes lisse et tuberculé (It), lisse (1) orné tuberculé (ot) et orné (0). L’analyse de groupe appliquée au déterminisme du facteur lisse exclut la salinité comme agent déterminant. La variation de température du milieu est proposée comme agent responsable du facteur lisse. ABSTRACT The disappearance of ornamentation, or smooth factor and its modalities are studied in different marine species such as Leptocythere pentagonalis Carbonnel and Elofsonella amberii Carbonnel or in brackish species as Cythero- morpha sp. Kuster-Wendenburg and Hemicypridets dacica grekoffi Carbon- nel and ev entually lacustrine species as Eucypris? grisiensis Margerie, Eucy- pris? tenuistriata straubi Carbonnel, Ritzkowski and Limnocythere n. sp. The scanning electron microscope observation allowed the discovery of new anatomical structures which are exclusive of smooth shapes, viz verrucae and area polyporea. Their physiological meaning still remains unknown. The correlation between the smooth factor and the apparition of tubercules has led to the definition of the smooth and ornate (It), smooth (1), ornate and tuberculated (ot) or ornate (0) morphotypes. Cluster analysis applied to the determination of the smooth factor excludes salinity as a determining agent. Variation of temperature in the biotope is taken as the responsible agent for the smooth factor. INTRODUCTION L’importance accordée jusqu’a présent dans la description systématique des Ostracodes a l’ornementation justifie en retour celle que l’on doit attribuer a sa régression chez ces mémes espéces. On entendra par facteur lisse la dispari- tion ou la régression de l’ornementation observée habituellement chez une espéce: cOtes, ponctuations, fossettes, réticulations etc. . . Ce concept ne s’ap- pliquera pas a la disparition des tubercules (phénotypiques ou génotypiques, selon les auteurs), éventuellement apparus sous certaines conditions écologiques. Un nombre trop restreint d’auteurs se sont intéressé jusqu’alors a ce phénoméne et a ses modalités. C’est une lacune que ce travail se propose de combler partiellement. On envisagera ici les modifications anatomiques a la suite de la disparition de l’ornementation et sa liaison avec la présence des tubercules (phénotypiques ou génotypiques). L’analyse du déterminisme du facteur lisse conduira 4 proposer la variation de la température comme agent déterminant. 286 G. CARBONNEL HISTORIQUE Dés 1960 V. Stchépinsky signalait l’existence (chez Cytheridea gilletae) de valves lisses 4 coté de valves ornées. Mais la premiére étude synthétique im- portante a été celle de Ph. Sandberg (1964). Il a indiqué l’existence de la disparition de |’ornementation chez plusieurs espéces (tabl. 2), invoquant l'abaissement de la salinité comme déterminisme écologique de ce phénomene. En 1967 G. Carbonnel a montré l’existence du méme phénoméne chez Elofsonella amberii. 11 en rendait également responsable une baisse de la salinité du milieu. Plus récemment, R. H. Benson (1969) soulignait 4 propos d’un repré- sentant de Limnocythere (du Pleistocene ancien de Rita Blanca Lakes) que les espéces de ce genre acquiérent une ornementation plus accentuée, lorsque l’eau douce de leur biotope devient plus salée. I] reconnaissait toutefois, quel- ques lignes auparavant, que le probléme n’était pas résolu! En 1969 G. Carbonnel (im G. Carbonnel et S. Ritzkowski) signalait encore existence du facteur lisse chez une forme lacustre de |’Oligocéne : Eucypris ? tenuistriata straubi. Au dernier symposium sur la Paléoécologie des Ostracodes (Pau, 1971) divers auteurs ont évoqué ce phénoméne. En particulier W. Ohmert (p. 611) a constaté, lors de l’étude des formes laguno-marines du Crétacé, une relation entre la réduction de l’ornementation et la diminution de la profondeur. H. Jordan et M. J. M. Bless (1971, p. 683 et suiv.) ont observé parmi diverses modifications, une réduction de l’ornementation chez une espéce du genre Cypridea. D’aprés ces quelques renseignements bibliographiques les espéces a facteur lisse sont taxinomiquement variées; elle vivent en milieu lacustre, saumatre ou marin. Le déterminisme de ce facteur est variable (salinité profondeur, ou autre((S))es-se1- ), mais mal connu et peu étudié. REPARTITION SYSTEMATIQUE, GEOGRAPHIQUE ET ECOLOGIQUE DES ESPECES ETUDIEES Elle est indiquée sur la tableaux 1 et 3. Il ressort de ces répartitions que le facteur lisse est un phénoméne général, largement réparti dans Je temps et probablement indépendant de la chlorinité du biotope originel de l’espéce. MODALITES MORPHOLOGIQUES DE L’APPARITION DU FACTEUR LISSE Chez Limnocythere, n. sp. (Pl. 2, figs. 10-20) (environ 500 individus observés) Le morphotype orné, considéré comme “normal”, est trés rarement repré- senté au sein des populations. L’ornementation est essentiellement constituée Especes N. échant Cytheromorpha 1353 sp. a L353 1353 1353 Elofsonella 1350 amberii 1350 1350 1353 a 1353 Eucypris? 1353 grisiensis 1353 1353 a 1353 1353 Eucypris? 2 tenuistriata straubi 1353 Hemicyprideis 1353 dacica grekoffi a Leptocythere 1350 pentagonalis 1350 Limnocythere n. sp. I3D3 12}5)5" 1353 33 11353 1353 1353 353 1353 S53 USE 1354 1 ; Exemplaires conse Pasteur, 69-Lyon 7 2 : Exemplaires conse1 Fédérale. Especes uw cytheromorpha sp. Blofsonella amberii Eucypris? grisiensis Eucypris? tenuistriata straubi Hemicyprideis dacica grekoffi Leptocythere pentagonalis Limnocythere Nn. sp. kemplaires conservés au Département Sciences de la Terre, eur, 69-Lyon 7eme, France no échantillon 135358" a 135362 135380 135382 2 135008 135009 135018 135336 a 135338 135339 135340 135343 a 135357 135386 2 638-142 135341 135326 a 135328 135046 135047 135363 iS 53167, 135368 135387 135385 135384 135369 Vs53i7'2 135364 135366 135370 3537. 135383 Tableau 1, ¢ 2 , Denomination de la coupe la Savoyonne Cairanne Roaix les Eyssa- rettes Grisy-les- “ Pléetres ris Rogieres Borken Al- tenburg IV Carry-le-Rouet la Savoyonne TTT L577 20 27 ires conservés au Geolog. Paldontol. Institut, Formation Untere Hydrobien- Schichten ‘ a Ostrea crassissima SS te ‘a Nystia- Melanopsis pararécifale du Cap des Nautes/ bioclastique de Carry; biodétritique de Sausset-les-Pins ‘a Ostrea rane crassissima Répertoire du Matériel Etudié é Etage Aquitanien Tortonien Bartonien Bartonien Sannoisien Aquitanien Tortonien Sannoisien " Stampien Bartonien Ludien Sannoisien " Ludien Stampien Stampien Oligocéne inf. Commune Mainz Visan Cairanne Buisson Puyméras Grisy-les- platres Rosiéres Carry-le-Rouet Visan Caseneuve Rustrel Apt Mallemont- du-Comtat Fontaine-de- Vaucluse 1l'Isle sur Sorgue vénasque Apt Apt Apt " Blauvac / Vénasque Gignac 34 Gottingen, Berliner-Strasse 28, Allemagne Département Vaucluse Seine et Oise Oise Bouches -du- Rhdne Vaucluse Vaucluse Université de Lyon Claude-Bernard, 86, rue ing . " WETD A + Mee TERTIARY OsTRACODES 287 Kassel e Borken Altenburg'l D Mainz 50° nGrizy-les- Platres © Rosieres a Lyon @ La Savoyonne Roaix OApt CarTy-le- Rovet Cairanne| ye ll o°? Limnocythere, 0. sp. Eucypris ? grisiensis Eucypris ? tenuistriata straubt Cytheromorpha sp. Hemicyprideis dacica grekoffi 2eae#e 0 Leptocythere pentagonalis % = Elofsonella amberii Text-figure 1. 288 G. CARBONNEL Tableau 3. Répartition géographique, litho- stratigraphique et &écologique des especes étudiées, & facteur lisse genre/espece localisation localisation chlorinité lithofacies géographique stratigraphique du x , du biotope “normal prélevement J ro fy Limnocythere, 254 sp. bassin du Oligocéne lacustre noOA Rhone Eucypris? grisiensis bassin de Eocene sup. lacustre sables argil- sy Margerie, Paris (Bartonien) eux et cal- = 1971 caires a argileux H & Eucypris? bassin de Oligocene lacustre @ tenuistriata la Hesse inf. straubi (Carb. Ritz, 1 1969) a x 3 3 Cytheromorpha Miocene zs 2G sp. Kuster- bassin de inf. saumatre calcaire- a8 Wendenburg, Mayence (Aquitanien) argileux 1970 u3 Hemicyprideis Miocéne saumatre sables argilo- BS dacia grekoffi bassin du inf. a calcaire & Of (Carb., 1969) Rhdne (Aquitanien) marin argiles 619 Leptocythere bassin du Miocene = = @ pentagonalis Rhone sup. marin calcaire G>nm (Carb, 1969) (Tortonien) argileux 40H ane 4 Elofsonella HmgQ amberii bassin du Miocene aed (Carb., 1969) Rhone sup. marin calcaire mon (Tortonien) argileux par des cellules polygonales, développées de préférence dans la moitié pos- térieure de la valve (PI. 2, figs. 10-12). Le morphotype lisse présente un stade intermédiaire (Pl. 2, fig. 13) avant d’acquérir la structure lisse. Dans ce cas l’ornementation subsiste dans la zone postérieure de la carapace. La facteur lisse est présent chez les larves. Tableau 2) © modifié d'aprés Sandberg Morphotypes Espéces Cyprideis ovata (Mincher) Cyprideis salebrosa van den Bold Cyprideis locketti (Stephenson) AMERIQUE -“‘Cyprideis pascagoulensis (Mincher) Cyprideis castus Benson Cytheromorpha calva Krutak ETATS-UNIS D Cytheromorpha ouachatensis Howe et Chambers Cytheromorpha paracastanea (Swain) Anomocytheridea inornata Stephenson Cytheridea gilletae Stchépinsky FRANCE Nombre de morphotypes observés .. Tableau 2 () Ostracodes presentant le facteur lisse modifié d'aprés Sandberg (1964, pl. I-III) et, Stchépinsky (1960, pl. 3) Morphotypes orné lisse lisse orné éces Beprce tuberculé tuberculé (1) (o) (ot) (1t) Cyprideis ovata (Mincher) + m Cyprideis salebrosa van den Bold 1: + Ay Cyprideis locketti (Stephenson) + de re Cyprideis pascagoulensis (Mincher) + Cyprideis castus Benson a + Cytheromorpha calva Krutak i + ETATS-UNIS D'AMERIQUE Cytheromorpha ouachatensis Howe et Chambers . + Cytheromorpha paracastanea (Swain) + * Anomocytheridea inornata Stephenson iy z Cytheridea gilletae 4 Stchépinsky . : ’ fay Nombre de morphotypes observes 4 0 8 10 4 ' i | . n “ 8} 8} ST UoI3;eyUeMIIpes eI sgide.p ‘9q1Ul[es ‘ginyelgduie4 8T 8T + 81 ate + + 8 8ST ’ ste + + + + 8 8 } T ee + 8 8 t i fe ST SI 8T ST ST ST 8T 8ST ST SI + ST 8} + eTqeqysur = Sst *sqe sedAjoyd sedféjoyd -10UI sep 94Inp -9P 97tur[es -10UI sep aqinp “9p o1ngeigdus4 + + + ste + + + + an ate + fe = + + + + + + + + + “12 + + as os + + ai a “uP ar ata oF Te cur iP + oP oF aP IF ats ar oie + + i + + + + cf + ot + oF + + + + + + + AF ar + + + + mF ar a + 1 + a + + + o19yy erayy o 40 I QW -AQOUUIL'T -A0ouwT'T *qny uou “qny *qn} uou *qny > < 9uio aSSTT SIAGIUdANOGN % edA,oydiour edsjoydiom 6/9FT O1L/9FT €/PST /BSE 6/90T 8I/FOL ST/F0T €1/F0L Z1/F0L OT/FOL 6/FOT L/¥0T G/POT 9/F0T ®2/P0L 23/F0T 8h/£0T 1Z/Z0T 0Z/Z0T TT/00T Z1/00T L/29 $1/SS L3/6F 93/6F 63/6F 61/6F 8/6F 91/6F 81/6F 08/6F SL/LB 33/LB ZI/LZ ¥2/LS LE/L3 €8/L3 SIQL 02 8/LLST SLING ST/L¥ET sjuour -9A9T9I1d sep ‘ON ‘Nayiu Np sinjergduiay Bf 39 yTUT[eS B] 9A UON[a1 Ina] ja ‘ds “U ‘a4ayshIOUMIT ZAYD SaArasqo sadkjoydsoy “fp NvaIqE,T, 290 G. CaRBONNEL Chez Eucypris ? grisiensis Margerie, 1972 (Pl. 1, figs. 2-4, 6-10). (200 individus observés) Les morphotypes ornés portent des stries longitudinales sur toute la surface. Certains présentent une anastomose de stries (PI. 1, fig. 2). Le morphotype orné tend a acquérir, par place (dans la zone dorsale, médiane ou ventrale) une structure lisse. Cette observation est, pour l’instant, limitée aux ostracodes présents dans deux prélévements du bassin de Paris (coupe de Rosiéres, Oise, niveau 602). Les morphotypes ornés de cOtes ana- stomosées, ne présentent pas ce stade intermédiaire. Des morphotypes entiérement lisses ou semi-lisses (Pl. 1, figs. 4, 6-10) existent suivant les lieux de prélévements. Les morphotypes semi-lisses con- servent encore la trace des cotes dans les zones périmarginales antérieure et postérieure. Les larves semblent de préférence aux adultes exprimer le facteur lisse. Chez Eucypris ? tenuistriata straubij Carbonnel, Ritzkowski, 1969. (PI. 1, figs. 1, 5). La réalisation de l’ornementation du morphotype orné est semblable a celle d’E. ? grisiensis (cf. Carbonnel, Ritzkowski, 1969, pl. 2, figs. 1, 2, 6). Le morphotype semi-lisse, avec costules antérieures et postérieures ré- siduelles, (cf. Carbonnel, Ritzkowski 1969, pl. 2, figs. 4, 5) est le seul ob- serve. Chez Cytheromorpha sp. Kuster-Wendenburg, 1969 (PI. 2, figs. 4-9). Le morphotype le plus orné posséde un réseau de cellules polygonales trés accentuées. Les morphotypes lisse ou a tendance lisse montrent une régression du réseau, particuliérement sensible dans la moitié postérieure (PI. 2, figs. 8-9). Dans le cas le plus regressé seules subsistent les fines ponctuations situées a lintérieur des mailles polygonales du réseau (PI. 2, fig. 9). Chez Hemicyprideis dacica grekoffi (Carbonnel, 1969). Les modifications de l’ornementation ont été étudiées précédemment (Car- bonnel, iz P. Andreiff, et al., 1971). On se bornera a rappeler que |’acquisition du facteur lisse est progressif. (Carbonnel, 1971, pl. 4, figs. 1, 4, 7, 11). La réduction de l’ornementation (chez l’adulte) commence dans Ja région antérieure. Chez Leptocythere pentagonalis Carbonnel, 1969( PI. 2, figs. 1-3). Le morphotype orné est essentiellement observé au stade adulte. Les morphotypes semi-lisses et lisses sont observés aux différents stades larvaires. La régression de l’ornementation peut se poursuivre jusqu’a la dis- parition des fossettes (Carbonnel, 1969, pl. 5, figs. 4-6). Elle débute dans la zone médiane et s’étend vers |’arriére et dorsalement. Chez Elofsonella amberii Carbonnel, 1967 (PI. 1, figs. 11-13). (185 individus observés) Le morphotype orné présente une réticulation entre les cdtes alors que le morphotype lisse en est dépourvu (pl. 1, figs. 11-2). TERTIARY OsTRACODES 291 CONCLUSIONS Des stades intermédiaires dans la régression de l’ornementation existent chez tous les exemples étudiés. Leur nombre et |’importance de ]’ornementation résiduelle sont variables selon les espéces. L’acquisition de la structure lisse débute toujours chez une espéce dans le méme zone, mais cette derniére est variable suivant les espéces. Les larves comme les adultes semblent affectés par ce facteur. MODIFICATIONS ANATOMIQUES CHEZ CERTAINS MORPHOTYPES LISSES Elles concernent Eucypris ? grisiensis Margerie et Elofsonella amberit Carbonnel. Microtubercules ou verrucae (Pl. 1, figs. 8-9). Des microtubercules supplémentaires, assimilables aux verrucae}, sont visibles dans la région médio-dorsale sur un exemplaire entiérement lisse d’E. ? grisiensis. Ils sont dépourvus de pores sétigéres. Au grossissement utilisé (x 1100 environ) la surface elle méme parait granuleuse. Les morphotypes semi-lisses, adultes ou larvaires, en sont dépourvus quelle qu’en soit la provenance géographique. Aréa polyporée (Pl. 1, fig. 13). On note la présence d’une surface percée de nombreux pores de petite taille vers l’extrémité antérieure de la cote médiane chez Elofsonella amberit, sur le morphotype lisse. L’aréa polyporée est inconnue chez les autres morpho- types. Les autres espéces étudiées ici ne présentent pas, jusqu’a présent, de modi- fications semblables du systéme porifére ou de la surface des valves. L’acquisition du facteur lisse influe parfois sur les micro-structures de la carapace de facon variable. La répercussion de ces modifications sur le com- portement physiologique nous échappe encore. LE FACTEUR. LISSE PLES TUBERCULES “PHENOTYPIQUES” Quelques espéces présentant le facteur lisse peuvent également porter, dans certaines circonstances écologiques, des tubercules communément appelés tubercules “phénotypiques’’. I] s’agit de: Limnocythere, n. sp. Cytheromorpho sp. Kuster-Wendenburg Hemicyprideis dacica grekoffi Carbonnel L’analyse a porté sur 40 prélévements ayant fourni des adultes et des larves appartenant a L., n. sp. On a pu constater |’existence: de morphotype a la fois lisse et tuberculé, /t’, (Pl. 2, figs. 16-18) représentant 25% de la population,® de morphotype lisse et non tuberculé, /.* (Pl. 2, fig. 15) repré- 1Selon la terminologie de P. C. Sylvester-Bradley, 1971. *L’assimilation des formes figurées par Ph. Sandberg 1964 a ces morphotypes est indiquée sur le tableux 2. 8La somme en pourcentage peut étre supérieure a 100, un prélévement pouvant présenter simultanément plusieurs morphotypes. 292 G. CARBONNEL sentant 90% de la population, de morphotype orné et tuberculé, O0# (PI. 2, fig. 11), représentant 5% de la population et de morphotype orné et non tuberculé 0° (PI. 2, figs. 10, 12) repréentant 15% de la population. On retiendra de ces pourcentages |l’indépendance des facteurs lisse et tuberculé. Cette indépendance est confirme chez Cytheromorpha sp. Kuster- Wendenburg, espéce chez laquelle les tubercules apparaissent sur des larves trés ornées (Pl. 2, fig. 4). Il en est de méme chez Hemicyprideis dacica gre- koffi ot les tubercules semblent s’atténuer et méme disparaitre sur les mor- photypes lisses (cf. Carbonnel, 1971, pl. 4, figs. 5, 11). On peut raisonnable- ment déduire de ces constatations que la disparition de l’ornementation est relativement indépendante de l’apparition des tubercules. Cette déduction acquerra une grande importance dans |]’étude du déterminisme de ce phéno- mene. ETUDE DU DETERMINISME DU FACTEUR LISSE 1) Variation de la chlorinité. La présence temporaire, suivant les prélévements, du facteur lisse chez une espéce implique probablement un déterminisme écologique. Compte tenu de l’indépendance pressentie entre les facteurs lisse et tuberculé, leurs déter- minismes doivent étre différents. La voie expérimentale directe, interdite au géologue, consisterait a faire varier l’amplitude des paramétres réputés actifs sur la biologie des ostracodes: la chlorinité (teneur en NaCl] du milieu), la température, la concentration en O., le pH, etc. . . On observerait alors les modifications morphologiques éventuelles. On devra toutefois se contenter d’une approche géologique, c’est-a- dire indirecte, du phénomeéne. 2) Calcul du taux de liaison par ]’analyse de groupe (W.P.G.M.) entre le facteur lisse observé chez Limmnocythere, n. sp. et le genre saumatre Neo- cyprideis. On peut étudier par cette méthode, le taux de liaison entre les divers morphotypes précédemment définis (/t, /, ot, 0) et la présence, l’absence et la dominance du genre Neocyprideis. Ce dernier, réputé saumatre, constitue alors une référence de la chlorinité du milieu. Le dendogramme de la figure 2, obtenu a partir du coefficient de Jaccard, traduit le degré de liaison entre ces “parametres”. On constate que le facteur lisse est associé 4 une population parmi laquelle le genre Neocyprideis n’est pas prédominant. Ce facteur n’est donc pas inféodé a une chlorinité réduite. 3) Calcul du taux de liaison par l’analyse de groupe (W.P.G.M.) entre le facteur lisse observé chez Hemicyprideis dacica grekoffi et la chlorinité ob- tenue par l’analyse sédimentologique. Dans cet exemple, la chlorinité a été uniquement déduite des études sédimentologiques. (P. Andreiff, R. Anglada ef al. . .. 1971). L’analyse de groupe permet d’établir le taux de liaison trés faible entre la diminution de la chlorinité et le facteur lisse comme le montre le dendogramme de la figure 3, obtenu a partir du coefficient de Jaccard. Coefficient de Jaccard oO 0,5 ! ! 1 ' ' \ I 1 I ' i] \ t t niveaux avec Neocyprideis dominant 1 morphotype lisse non tuberculé niveaux sans Neocyprideis morphotype lisse tubercule niveaux avec Neocyprideis non dominant morphotype orné non tuberculé morphotype orn¢ tuberculé Figure 2. Dendogramme (coefficient de Jaccard, W.P.G.M.) des morpho- types de Limnocythere, n. sp. et du genre Neocyprideis dans les bassins oligo- céenes d’Apt, Pernes et Mormoiron. Coefficient de Jaccard 0,5 1 SST >= le > Le) Pa ee ee a aaa cae | Hes SS BE eae —_EEOREE gO ait nee EL Hemicyprideis helvetica nerthcensis CARBONNIE_L Cyamocy theridea sp. Cy theridea acuminata caumontensis CARBONNEL Propontocypris solitaria CARBONNEL Eocvtheropteron bruggenense OF RTLI Costa tricostata subsp. I n. subsp. Morphotype orné d’Hemicyprideis dacica grekoffi (CARBONNI'L) Quadracy there ct. nodoreticulata BASSIOUNI Hemicypridets dacica grekoffi (C ARBONNEL) Morphotype lisse d’Hemicyprideis dacica grekoffi Salinite euhaline Quadracy there confluens xeniae MOOS Callistocyv there savovonnei CARBONNEL Cytheretta ct. ovata (EGGER) Falunia sphaerulolineata (JONES) Cy theretta ct. accedens (UGGER) Krithe “‘bartonensis”’ (JONES) Miocyprideis aff. rara rara (GOERLICH) Hemicyprideis helvetica tendance grekoffi Procythereis cf. deformis (REUSS) ; Loxoconcha sp. Salinité saumatre Loxoconcha hastata (RUSS) Schuleridea cf. occulata MOOS Hermanites haidingeri (RE USS) Salinité limnique Hemicy therideis sp. Figure 3. Dendrogramme (coefficient de Jaccard, W.P.G.M.) des ostra- codes associés a Hemicyprideis dacica grekoffi (Carb.,) (morphotypes lisses et ornés) et de la chlorinité du milieu, dans la coupe de Carry-le-Rouet. 294 G. CaRBONNEL 4) Conclusions Ces deux analyses confirment l’indépendance du facteur lisse (de son apparition et de sa persistance) par rapport a la baisse de la chlorinité de leau. Elle avait été pressentie par l’auteur en 1969 a propos des morphotypes semi-lisses d’E. ? tenuistriata straubi Carbonnel et Ritzkowski (de l’Oligocéne de la Hesse). L’observation de ces morphotypes comme de ceux rapportés ici a E. ? grisiensis (de |’Eocéne du bassin de Paris) en milieu lacustre, interdit d’envisager une baisse de la chlorinité comme agent déterminant. Le déter- minisme de ce facteur doit étre recherché dans une autre direction. 5) Variation de la Température O. Kinne, dans diverses publications (en particulier 1964) a montré importance des couples température-salinité-concentration en oxygéne du milieu, sur le comportement physiologique des Crustacés. D’aprés ce qui précéde, la chlorinité étant exclue comme agent déterminant, peut-on con- sidérer une variation de la température comme responsable de l’apparition de facteur lisse? En |’absence de mesures de paléo-températures, l’approche de ce probleme sera encore indirecte. Jusqu’a présent aucune indication sur la température ne peut étre obtenue a partir des prélévements ayant livrés Eucypris ? grisiensis, E. ? tenuistriatus straubi, Elofsonella amberii et Leptocythere pentagonalis. La majorité des niveaux de la coupe de Carry-le-Rouet ayant livré Hemi- cyprideis dacica grekoffi est caractérisée par une eau tempérée chaude d’aprés la macrofaune (fro parte) et certains foraminiféres. On aura garde en outre d’oublier l’existence de formations récifales a plusieurs niveaux de la coupe. Une seconde preuve de |’influence de l’augmentation de la_ température nous est fournie par |’environnement des niveaux a Limmocythere, n. sp. Il s’agit de prélévements intercalés au sein d’un complexe évaporitique, gypseux, de l’Oligocéne (J. M. Triat, et G. Truc 1972). On exclura, compte tenu de ce qui précéde, une baisse de la température comme agent déterminant. De plus, l’analyse du rapport hauteur/longueur de la valve chez Elof- sonella amberij et Eucypris ? tenuistriata straubi, morphotypes lisses et ornés, ne révéle aucune augmentation de taille. En effet, elle devrait se produire dans un milieu a basse température (cf. J. Szczechura, 1971 pour |’étude la plus récente de ce phénoméne). L’ensemble de ces arguments tend a accréditer l’hypothése d’une augmenta- tion de la température de l’eau comme déterminisme du facteur lisse. Des phénoménes analogues concernant la disparition de caractéres ornementaux ont été décrits et étudiés expérimentalement chez Daphnia retrocurva et Daphn- ia galeata (J. L. Brooks, 1946). La disparition de l’épine sommitale de la téte résulte d’aprés ces études d’un abaissement de la température, a |’inverse des Ostracodes. TERTIARY OsTRACODES 295 INTERPRETATION DES MORPHOTYPES LT, L, OT, O Il ressort de l’analyse précédente qu’une élévation de la température du milieu peut se manifester par ]’apparition du facteur lisse. Il est en outre admis qu’une variation de la salinité peut se traduire par la production de tubercules. L’observation dans un prélévement de morphotypes appartenant au groupe: — ot: indiquerait un milieu a chlorinité variable, a température constante — /t: indiquerait un milieu a chlorinité variable, 4 température variable en hausse — /: indiquerait un milieu a chlorinité constante, a température variable en hausse — o: indiquerait un milieu a chlorinité constante, 4 température constante. Application aux prélévements oligocénes a Limnocythere n. sp. Confirma- tion de la température comme agent déterminant du facteur lisse. Les 4 premiéres colonnes du tabl. no. 4 indiquent pour chaquh prélévement la nature des morphotypes observés. La présence du genre Neocyprideis et son abondance, relativement a la population de Limnocythere, n. sp., sont inscrites dans les 3 colonnes suivantes. Dans les 2 autres colonnes sont figurées |’interpré- tation de la température et de la salinité du milieu; elle est déduite des morpho- types présents dans les 4 premieres. La confirmation ou |’infirmation de linterprétation du milieu par l’analyse sédimentologique est mentionnée dans la derniére colonne. Dans l’ensemble, la confirmation apportée par ces études sédimentologiques nous autorise a proposer la variation de température comme déterminisme susceptible de provoquer, chez certains ostracodes, l’apparition du facteur lisse. ESSAI DDINTERPRETATION PHYSIOLOGIQUE DU FACTEUR LISSE O. Kinne (1966) a souligné que le degré de résistance des organismes est augmenté lorsque la concentration en calcium des cellules croit corrélativement. Le facteur lisse correspond, sans doute, 4 une diminution de la. consomma- tion du calcium au profit d’une rétention potentielle plus élevée de cet élément a |’intérieur du liquide cellulaire; cela permettrait d’étendre |l’interprétation de O. Kinne a certains Ostracodes. REMERCIEMENTS Je tiens a remercier particuliérement P. Margerie (Argenteuil, France), E. Kuster-Wendenburg (Mainz, Allemagne Fédérale) et M. Castel (Mont- pellier, France) pour |’amabilité avec laquelle ils m’ont permis d’utiliser leur matériel. Mes remerciements vont également a J. M. Triat (Marseille) et G. Truc (Lyon) pour |’autorisation de mentionner leurs résultats stratigraphiques et sédimentologiques. 296 G. CARBONNEL BIBLIOGRAPHIE Andreiff, P., Anglada, R., Carbonnel, G., Catzigras, F., Cavelier, C., Chateauneuf, J. J., Colomb, E., Glintzboeckel, Ch., Jacob, C., Lay, J., Lezeaud, L., Lhomer, A., Lorenz, C., Mercier, H., Parfenoff, A. 1971. Contribution a étude de l’Aquitanien. La coupe de Carry-le-Rouet, Bouches-du-Rhéne, France, Bull. Bur. Rech. géol. min., Paris, Sect. 1, No. 4, 135 p., 17 pls. Benson, R. H. 1969. Ostracodes of the Rita Blanca lake deposits. Geol. Soc. America, Mem., No. 113, pp. 107-115, pl. 21-22. Brooks, J. L. 1946. Cyclomorphosis in Daphnia I. Analysis of D. retrocurvata and D. galeata. Ecol. Monogr., vol. 16, No. 4, pp. 409-447, 18 figs. @ Carbonnel, 1967. Variations phénotypiques chez une espece tortonienne du genre Elofsonella Pokorny. In The taxonomy, morphology, and ecology of recent Ostracoda, Oliver and Boyd édit., Edinburgh, pp. 85-92, ie pleletios 1969. Les Ostracodes du Miocéne rhodanien. Systématique, biostratigra- phie écologique, paléobiologie. Thése. Docum. Lab. Géol. Fac. Sci. Lyon, no. 32, fasc. 1-2, 469 p., 48 figs., 57 tabls., 16 pls. Carbonnel, G., et Ritzkowski, S. 1969. Ostracodes lacustres de I’Oligocéne, (Melanienton) de la Hesse (Allemagne), Arch. Sc., Genéve, vol. 22, fasc. I, pp. 55-82, figs. 1-4, pls. 1-5. Jordan, H., et Bless, M. J. 1971. Eine inverse Cypridea aus dem Oberen Jura von Teruel (Spanien). Bull. Centre Rech. Pau, SNPA, vol. 5, suppl., pp. 683-693, 2 pls., 2 figs. Kinne, O. 1964. Non genetic adaptation to temperature and salinity. Helgol. Wiss. Meeresunters., vol. 9, No. 1-4, pp. 433-458, 8 figs. 1966. Physiological aspects of animal life in estuaries with special reference to salinity. Nether]. Jour. Sea. Res., vol. 3, No. 2, pp. 222-244, 9 figs., 2 tabls. Margerie, P. 1972. Essai de “quantification” du contour des ostracodes a l’occasion de la description d’une nouvelle espéece de Cypridinae du Mari- nésien du Bassin de Paris. Rey. Micropaléontol. Paris. vol. 14, No. 4. pe 227-235. Ohmert, W. 1971. Ecology of some Trachyleberididae (Ostracoda) from the Bavarian Upper Cretaceous, Bull. Centre Rech. Pau, SNPA, vol. 5, suppl., pp. 601-614, 7 figs. Sandberg, P. 1964. Notes on some Tertiary and Recent brackishwater Ostracoda. Pubbl. Staz. zool. Napoli, vol. 33, suppl., pp. 496-514, 3 pls., 1 fig. Stchepinsky, A. 1960. Etudes des Ostracodes du Sannoisien de l’Alsace. Bull. Serv. Carte Alsace-Lorraine, Strasbourg, t. 13, fase. I, pp. 11-34, 3 pls. Sylvester-Bradley, P. C. et Benson, R. H. 1971. Terminology for surface features in ornate ostracodes. Lethaia, vol. 4, No. 3, pp. 249-286, 48 figs. TERTIARY OsTRACODES 297 Triat, J. M., et Truc, G. 1972. L’oligocéne du bassin de Mormoiron (Vaucluse). Etude paléonto- logique et sédimentologigue. Docum. Lab. Gélo. Fac. Sci. Lyon, No. 49, pp. 27-52, 1 pl., 2 figs., 1 tabl. Szezechura, J. 1971. Seasonal changes in a reared fresh-water species, Cyprinotus (Heterocypris) incongruens (Ostracoda), and their importance in the interpretation of variability in fossil ostracodes. Bull. Centre Rech. Pau, SNPA, vol. 5, suppl., pp. 191-205, 1 pl., 7 figs., 1 tabl. Wendenburg, E. K. 1969. Mikrofaunistiche Untersuchungen zur Stratigrafie und Okologie der Hydrobienschichten (Aquitan, Untermiozdn) im Gebiet der Stadt Mainz-am-Rhein. Notizbl. hess. L-Amt Bodenforsch., Wies- baden, vol. 97, pp. 229-242, 2 figs., 2 tabls., pls. 8-10 G. Carbonnel, Université Lyon 1-Claude Bernard, Département des Sciences de la Terre, 69 Villeurbanne, France, 298 G. CARBONNEL Planche 1 Figure 1,5. Eucypris ? tenuistriata straubi Carbonnel, Ritzkowski (x 55) 1. vg., paratype No. 135341/1, Borken Tagebau Altenburg IV Melanienton; morphotype orné. 5. vg., paratype No. 135341/2, Borken Tagebau Altenburg IV, Melanienton; morphotype semi- lisse. 2-4, 6-10. Eucypris ? grisiensis Margerie (2-4, x 55) 2. vd., No. 135345, Rosiéres niveau 602/10, Bartonien; morpho- type orné a stries anastomosées. 3. vd., No. 135339, Grisy-les- Platres, Bartonien; morphotype orné. 4. vd., No. 135344, Rosieres, niveau 602/10, Bartonien; morphotype semi-lisse. 6. vd., No. 135386 (x 55), stade larvaire, Grisy-les-Platres, Bartonien; morphotype lisse. 7. vd., No. 135386 (x 265). 8. vd., No. 135386 (< 540), détail de la zone médio-dorsale. 9. vd., No. 135386 (x 2700), détail d’un microtubercule ou verrucae. 11-13. Elofsonella amberii Carbonnel 11. vg., No. 135337 (x 50), Cairanne, Tortonien; morphotype lisse’ a cotes, 12, vg. No. 135337. (xX J00)e sa ven New ts5o50 (X 800), détail de |’aréa polyporée. Z99 TERITARY OsTRACODES Plate 1 Plate 2 G. CARBONNEL : re R > TERTIARY OsTRACODES 301 Planche 2 Figure 1-3. Leptocythere pentagonalis Carbonnel (x 70) 1. vd., No. 135363/1, adulte, la Savoyonne niveau 104 f, Tor- tonien; morphotype orné. 2. vd., No. 135363/2, stade larvaire ?; morphotype a tendance lisse. 3. vd., No. 135363/3, stade larvaire ?; morphotype semi-lisse. 4-9. Cytheromorpha sp. Kuster-Wendenburg, Mainz, Aquitanien 4. vg. No. 135380, stade larvaire (xX 110); morphotype orné tuberculé. 5. vg., No. 135381, stade larvaire (X 110); morpho- type orné. 6. vg., No. 135382, male (XX 85); morphotype orné. 7. vg., No. 135360, male (x 140); morphotype orné, 4 ornementa- tion atténuée. 8. vg., No. 135359, male (x 85); morphotype a tendance lisse. 9. vg., No. 135358, male (xX 55); morphotype lisse. 10-20. Limnocythere, n. sp. 10. vd., No. 135371, femelle ( 65); collection M. Castel niveau 926, Oligocéne inférieur; morphotype orné. 11. vg., No. 135369 (x 55); Apt niveau 102/20, Ludien; morphotype orné tuberculé. 12. vd., No. 135368, male (x 70); Mallemort-du- Comtat niveau 27/72, Stampien; morphotype orné. 13. vd., No. 135383, male (x 60); collection M. Castel, Gignac niveau 926 Oligocene inférieur; morphotype orné a tendance lisse. 14. vd., No. 135367, male (x 55); Mallemort-du-Comtat niveau 27/72, Stampien; morphotype semi-lisse. 15. vg., No. 135372 male (X 65); Apt niveau 102/20, Ludien; morphotype lisse. 16. vg., No. 135370, male (xX 70); collection M. Castel; Gignac niveau 926/1, Oligocéne inférieur; morphotype lisse avec un tubercule ventral ébauché. 17. vd., No. 135364, male (xX 70); Blauvac niveau 122, Ludien; morphotype lisse tuberculé. 18. vd., No. 135366, stade larvaire (xX 70); Blauvac niveau 122, Ludien; morphotype lisse tuberculé. 19. vg., No. 135385, femelle vue dor- sale (xX 110), Fontaine-de Vaucluse niveau 49/29, Stampien; morphotype orné. 20. vd., No. 135384, male vue dorsale (x 110), Fontaine-de-Vaucluse, niveau 49/29, Stampien; morphotype orné. MUDLUMP OSTRACODA H. V. Howe* anv W. A. VAN DEN Bop Louisiana State University ABSTRACT Mudlumps are intrusive clays that have penetrated into and through bar deposits near the mouths of Mississippi River Passes. They may occur above or below sealevel and about a hundred of them have been mapped. Radiocarbon date on Foraminifera from these deposits is 15,000 years before present, on macrofossils 15,500 years. Ostracoda are listed from three of the mudlumps. Each of the three samples contained more than 50 species, which is well above the number found in any Recent samples from the Gulf of Mexico. The Ostracoda are very well preserved and their distribution sug- gests deposition at a depth of approximately 100 feet. No formal descriptions are given, but SEM photographs are shown for all but the rarest species (Plates 1-3). Several species indicated in the list as new have been described erroneously under different names by previous workers. RESUME Les iles de boue du delta du Mississippi a “pied d’oiseau’’ sont des struc- tures d’argiles diapyriques qui ont pénétré les sediments sableux marginaux des bouches. On en a régistré une centaine. Détermination de l’age de ces dépots a base de C!4 sur des foraminiféres a donné 15000 ans, sur des macrofossiles 15500. Nous présentons une liste des ostracodes de trois de cettes iles de boue. Chacun de ces trois échantillons a fourni plus de 50 spécies, un nombre plus élevé de que l’on a encontré dans aucun échantillon actuel dans le Golfe de Mexique. Les ostracodes sont bien préservés et leur répartition sugére une déposition 4 une profondeur d’environ 100 pieds. Nous avons évité des descrip- tions formales, en contraire nous présentons des photographies SEM de toutes les espéces sauf les plus rares (Planches 1-3). Plusieurs espéces représentées dans la liste ont été décrites antérieurement sous des noms différents par des autres auteurs. OSTRACODA OF MUDLUMP SAMPLES The unique “bird’s foot” delta of the Mississippi River is characterized, at the tips of its toes, by curious structural features which during the past 200 years have come to be known as “mudlumps.” They were well illustrated by Sir Charles Lyell in his Principles of Geology (Eleventh Edition, volume 1, pages 442-459). The term “mudlump” is a popular name for the upswellings of clay which occur just beyond the mouths of the Mississippi River passes. They may occur as shoals, or if active, as distinct mud islands. Detailed studies of these mudlumps have been made by J. P. Morgan (1961, 1963) which con- clusively show that they are diapiric (intrusive) folds of clay thrust into and through the bar deposits, accompanied by low angle thrust faults, which have displaced the clay units vertically as much as 350 to 400 feet to their present subaerial position. The foraminiferal content of the mudlump clays has been described by H. V. Andersen (1961). In the region of South Pass, Dr. Morgan has mapped the occurrence of over 100 of these mudlumps, here reproduced as Text-figure 1. The structural relationship of the fossiliferous clays, Unit II, is shown on Text-figure 2, from a portion of a section figured by Morgan (1963, fig. 11). Through the kindness of Dr. Morgan, the senior author was supplied with a sample from mudlump 89-90 (now one island) and called SP-1 in Andersen’s *Deceased September 27, 1973 304 H. V. Howe anp W. A. vAN DEN Bop @©”' SUBMARINE LUMP a“ MUDLUMP ISLAND (Number coincides with Fig. 3) 800 1600 2400 196) Shore/ine Text-figure 1. Mudlump distribution South Pass. Data from 123 maps dated between 1867-1961. (After Morgan, 1963, fig. 2.) Mupiump OstTrRAcoDA 305 == eae —— =n Sac aaes \ ( ) TD -701" Text-figure 2. Cross section illustrating mudlump structure in South Pass area. (After Morgan, 1963, fig. 11.) 1961 report. He also supplied material from mudlump 94 which has become an island since 1963. Dr. Andersen supplied the junior author with material from his most prolific locality, mudlump SP-5 (No. 91 on Text-fig. 1) which has become a shoal since the map was made. One of the most interesting features of this fossiliferous, very plastic clay is its extremely fine grain. All of the non-organic material passes a 200- mesh sieve. This is even true of the layer referred to as shell horizon, or “Shell hash” in Morgan’s report. Gagliano’s (1963) report on these clays showed that they were not derived from the Mississippi River, but from the Southern Appalachians. It must be assumed that the Mississippi River, at the time these clays were deposited, was occupying the Submarine Canyon south of the city of Houma, approximately 100 miles west of its present mouth. The 306 H. V. Howe anp W. A. VAN DEN BoLp radiocarbon date for the deposition of these clays has been set at 15,000 years on Foraminifera, and 15,500 years on the macro-shells of the shell bed according to Dr. Morgan. The preservation of the Foraminifera and Ostracoda is as good as that of living specimens. Whether one considers them to be Recent or Pleistocene in age, it should be noted that Cvancara, et al. (1971, p. 172) remarked that “Active glacial ice existed in the general area [of southeastern North Dakota] until about 13,000 years before the present (B.P.).” Delorme described the fresh-water Ostracoda in that report. Dr. Andersen, during the years 1948-1950, obtained over 200 species of Foraminifera from his mudlump samples. Most of them came from the shell layer on mudlump SP-5 (91). His samples from SP-1 contained brackish water assemblages of Unit I as shown in Text-figure 2 such as are characteristic of the prodelta clays of the present Mississippi. Thrusting has continued at this area and the shell bed, and perhaps 4 feet cf overlying very fossiliferous clay of Unit II, are now exposed with mudlumps 89 and 90 united at the present time. The sample described in this report from 89-90 came from soft mud inside the shell of a giant snail Touma. Ostracoda are naturally not as abundant and diverse as Foraminifera in these samples, but the more than 60 species we have obtained are far more than have been reported from any samples we know of from the northern shelf of the Gulf of Mexico (checklist). This is not a near-shore fauna. However, the abundance and variety of genera and species indicates that it lived within the phytal zone at a depth probably closer to 100 feet than the 450 feet where it is encountered in wells between the mudlumps. We plan to describe the new species later. ACKNOWLEDGMENTS We are grateful to Tom Choung for his help with the stereoscan pictures. Philip Larimore and Mrs. Judy Ardoin arranged the plates and figures. LITERATURE CITED Andersen, H. V. 1961. Foraminifera of the mudlumps, Lower Mississippi River Delta. Louisiana Geol. Sur., Bull. 35, part II, 209 pp, 29 pls. Gagliano, S. M. 1963. Clay mineralogy of south pass mudlumps. Louisiana St. Univ. Studies (Coastal Studies Series No. 10), Appendix C, pp. 73-97. Morgan, J. P. 1961. Mudlumps at the mouths of the Mississippi river. Louisiana Geol. Sur, Bull. 35); Pt. 1) 116 pps 61) fies: 1963. Mudlumps at the mouth of south pass, Mississippi River: Sedi- mentology, Paleontology, Structure, Origin, and Relation to Deltaic processes. Louisiana St. Univ. Studies (Coastal Studies No. 10), pp. 1-50. Cvancara, A. M., Clayton, L., Bickley, W. B., Jr., Jacob, A. F., Ashworth, A. C., Brophy, J. A., Shay, C. T., Delorme, L. D. and Lammers, G. F: 1971. Paleolimnology of late quaternary deposits: Seibold Site, North Dakota. Science, 171, pp. 172-174. Mupiump OsTRACODA 307 H. V. Howe and W. A. van den Bold, School of Geoscience, Louisiana State University, Baton Rouge, Louisiana, U.S.A. 70803 CHECKLIST OF OSTRACODA Checklist of Ostracoda from Mississippi River mudlumps. Columns list numbers of specimens in each of the three samples. SP-1 SP-5 (80-90) (91) 94 1. Actinocythereis n. sp.? + 14 21 2. Ambocythere exilis Bold, 1966 12 3. Argilloecia sp. 1 70 37 41 4. Argilloecia sp. 2 28 6 5. Aurila n. sp. (not A. conradi) 105 122 36 6. Aurila sp. aff. A. amygdala (Stephenson, 1944) 4 7. Bairdia sp. (fragment) 1 8. Basslerites minutus Bold, 1958 + 3 14 9. Buntonia n. sp. 3 6 31 10. “Bythocypris” ? sp. 1 1 11. Bythocythere sp. 76 58 28 12. Bythoceratina sp. 1 13. Cativella n. sp. 9 16 12 14. Cytherella n. sp. 1 9 16 15. Cytherella n. sp. 2 Zs 4 16. Cytherelloidea n. sp. 1 37 7 35 17. Cytherelloidea n. sp. 2 8 18. Cytheromorpha cf. C. apheles Bold, 1963 24 25 13 19. Cytheropteron sp. 1 138 69 54 20. Cytheropteron sp. 2 37 6 13 21. Cytheropteron horacecoryelli Puri, 1962? 13 22. Cytherura sp. 83 54 28 23. LEchinocythereis margaritifera (Brady, 1870) 159 377 91 24. Echinocythereis spinireticulata Kontrovitz, 1971 3 2 25. Eucythere sp. aff. E. triangulata Puri, 1954 3 2 5 26. Eucythere sp. 2 1 27. Eucytherura sp. 1 49 20 28. Eucytherura sp. 2 31 6 29. Henryhowella ex gr. asperrima (Reuss, 1850) 19 70 53 30. Hulingsina sp. aff. H. sulcata Puri, 1960 10 26 31. Hulingsina tuberculata Puri, 1958 145 157 44 32. Jugosocythereis pannosa (Brady) 1868 1 33. Kangarina sp. aff. K. ancycla Bold, 1963 77 18 14 34. Krithe [at least 2 sp.] 148 115 92 35. Loxoconcha sp. 1 117 123 86 36. Loxoconcha sp. 2 39 3 37. Loxoconcha sp. 3 [? = purisubrhomboidea of Grossman, 1965] 82 16 38. Loxoconcha fischeri (Brady, 1869) 1 39. Luvula sp. 13 2 40. Machaerina sp. 8 2 308 H. V. Howe anp W. A. vAN DEN Bop 41. Macrocyprissa sp. 21 13 6 42. Macrocyprina sp. 26 5 43. Macrocypris? sp. 12 44. Microcythere [several sp.?] 45 1 45. Munseyella n. sp., aff. M. bermudezi Bold, 1966 120 aif 20 46. New genus? aff. “Cytheromorpha” caudata Bold, 1966 7 1 47. Paracypris sp. 34 2 13 48. Paracythere sp. 1 3 49. Paracytheridea sp. 13 44 55 50. Paracytherois sp., aff. Paradoxostoma robusta Puri, 1954 31 51. Parakrithe sp. 3 52. Pellucistoma sp. 49 10 53. Polycope sp. 2 54. Propontocypris sp. 8 4 55. Proteoconcha gigantica (Ed.) Plusquellec & Sandberg, 1969 + 56. Protocytheretta, n. sp. aff. P. pumicosa (Brady, 1866) 9 7 16 57. Pseudocythere sp. 23 3 1 58. Pseudopsammocythere? or Parakrithella? sp. 12 4 5 59. Pterygocythereis, n. sp., aff. P. americana (Ulrich & Bassler) 74+ 26 71 60. Pterygocythereis, n. sp. 2 4 9 61. Pumilocytheridea sp. 1 62. Puriana, n. sp. 55 44 17 63. Sclerochilus sp. 1 26 7 8 64. Sclerochilus sp. 2 4 10 65. Semicytherura sp. 1 50 8 5 66. Semicytherura sp. 2 50 11 7 67. Semicytherura sp. 3 2 3 5 68. Xestoleberis sp. 25 10 46 Subtotals 2191 1597 1139 Total number of specimens 4927 DISCUSSION Dr. R. H. Benson: It is interesting that within the particular species of Echinocythereis, which you have, one can notice a change in the living form as they go deeper. They become larger and less coarsely spinose. But the most important thing I think is the change in the size of the eye tubercle. As you know, the ones living in shallow waters today have a very large tubercle. As you get material from deeper localities the eye tubercle gets smaller, until about 600 meters, which is deeper than yours, where it completely atrophies. This suggests that not only does Echinocythereis originate in this area, but it may be possible to show the depth of the water relative to the ability or need of the animal to see. It may be useful to trace the size and occurrence of the eye tubercles in fossil ostracodes as a means of indicating the amount of light and perhaps the depth of ancient sedimentary conditions. Dr. H. Howe: You see this is a very much larger fauna than you get in any samples that I know of taken out on the shelf of the Gulf of Mexico at the present time. Dr. J. E. Hazel: The fauna is actually very similar to what you get along the Atlantic coast south of Cape Hatteras, with some notable exceptions. Dr. Howe: Valentine’s paper shows this (P. C. Valentine U.S.G.S., Prof. Paper 683-D, 1971). 310 H. V. Howe anp W. A. VAN DEN BoLp EXPLANATION OF PLATE 1 Figure la,b. Actinocythereis, n. sp. aff. A. bahamensis (Brady, 1870) x 50 2: Ambocythere exilis Bold, 1966 x-75 3. Argillcecia sp. 1. x 75 4. Argilloecia sp. 2. x 75 5. Aurila, n. sp. aff. A. conradi (Howe & McGuirt, 1935) x 50 6. Aurila, n. sp. aff. A. amygdala (Stephenson, 1944) x 50 Ue Basslerites minutus van den Bold, 1958 x 75 8. Buntonia, n. sp. < 75 9. Bythocythere sp. x 60 10. Cativella, n. sp. aff. C. semitranslucens (Crouch, 1949) x 50 ial, Cytherella, n. sp. 1. « 50 12. Cytherella, n. sp. 2. x 50 13. Cytherelloidea, n. sp. 1. x 50 14. Cytherelloidea, n. sp. 2. « 50 15. Cytheromorpha sp. aff. C. apheles van den Bold, 1963 16. Cytheropteron sp. 1. x 75 ie Cytheropteron sp. 2. « 75 Figured specimens deposited in Museum of Geoscience, Louisiana State Uni- versity, numbers: HVH 9699-9716. Plate 1 Muptump OstTRACODA 312 H. V. Howe anv W. A. VAN DEN Bop EXPLANATION OF PLATE 2 iL. Cytheropteron horacecoryelli Puri, 1962? x 75 ae Cytherura sp. x 75 3a,b. Echinocythereis margaritifera (Brady, 1870) x 50 4 Echinocythereis spinireticulata Kontrovitz, 1971 «x 50 5 Eucythere sp. aff. E. triangulata Puri, 1954 x 75 6. Eucythere sp. x 75 tf Eucytherura sp. 1. x 100 8 Eucytherura sp. 2. x 100 9a,b. Henryhowella ex. gr. asperrima (Reuss, 1850) x 50 10. Hulingsina tuberculata Puri, 1958 x 50 lla,b. Kangarina sp. aff. ancycla van den Bold, 1963 x 75 12. Krithe sp. 1 x 75 13. Krithe sp. 2 x 75 14. Loxoconcha sp. 1. x 75 5: Loxoconcha sp. 2. x 100 16. Loxoconcha sp. 3. « 75 7s Loxoconcha fischeri (Brady, 1869) ~« 75 Figured specimens deposited in Museum of Geoscience, Louisiana State Uni- versity, numbers: HVH 9717-9736. Plate 2 Muptump OsTRACODA 314 H. V. Howe anp W. A. VAN DEN BoLp EXPLANATION OF PLATE 3 Figure te Luvula sp. x 75 De Macrocyprissa sp. x 50 3h Macrocyprina sp. x 50 4. Microcythere sp. 1 x 100 5. Microcythere sp. 2 « 100 6. Munseyella, n. sp. aff. M. bermudezi van den Bold, 1966 x 100 le New genus? aff. “Cytheromorpha” caudata van den Bold, 1966 x 8. Paracypris sp. x 50 9. Paracytheridea sp. « 50 10. Paracytherois sp. x 50 ial Pellucistoma sp. x 75 1px Propontocypris sp. x 50 13. Protocytheretta, n. sp. aff. P. pumicosa (Brady, 1866) x 50 14. Proteoconcha gigantica (Ed.) Plusquellec and Sandberg, 1969 x 50 105). Pseudocythere sp. x 50 16. Pseudopsammocythere? or Parakrithella? sp. x 70 A, Pterygocythereis, n. sp. aff. P. americana (Ulrich and Bassler, 1904) x 50 18. Pterygocythereis, n. sp. 2 x 50 19. Puriana, n. sp. x 50 20. Semicytherura sp. 3 x 75 All. Semicytherura? sp. 2 x 60 22. Xestoleberis sp. x 75 Figured specimens deposited in Museum of Geoscience, Louisiana State Uni- versity, numbers 9737-9758. Plate 3 Mupiump OstTRACODA OSTRACODE ECOLOGY DURING THE UPPER CRETACEOUS AND CENOZOIC IN ARGENTINA ALWINE BERTELS* Universidad Buenos Aires ABSTRACT Upper Cretaceous and Cenozoic marine strata are exposed in Argentina and mostly contain a well-preserved ostracode and foraminiferal] assemblage. This paper is a first attempt to infer some environmental changes from the Upper Cretaceous through the Cenozoic in Argentina by means of ostracodes. Foraminiferal assemblages associated with the ostracodes, well known as paleo- ecological indicators, were the principal aid for most of the interpretations. The principal factors that in the past influenced the distribution of marine Ostracoda are analyzed, the most important being water temperature, salinity, and depth. Temperature is the principal factor that has influenced the latitudinal distribution of the ostracode faunal assemblages; salinity and depth are also important controlling factors: some species show a tolerance to changes in these ecological factors whereas some other species are markedly restricted to definite environments. As a result of this study some temperature changes are registered during the Cenozoic and salinity and depth variations can be inferred in some basins. LA PALEOQECOLOGIE OSTRACODALE PENDANT LE CRETACEE SUPERIEURE ET LE CENOZOIQUE EN ARGENTINE RESUME De couches marins cénozolques et de la Crétacée supérieure se trou- vent exposés en Argentine, contenant pour la plupart un assemblage ostracodal et foraminiféral bien préservé. Le travail est une premiére tentative dans la direction d’inférer quelques changements paléoécologiques de Je Crétacée supérieure a travers le Cénozoique en Argentine, au moyen des ostracodes. Les assemblages foraminiféraux, associés avec les ostracodes et bien connus comme des indicateurs paléoécologi- ques, constituait l’aide principale pour la plupart des interprétations. Les facteurs principaux qui, dans le passé, ont influencé la distribution des ostracodes marins sont analysés, dont les plus importants sont la température de l’eau, la salinité, et la profondeur. La température de |’eau est le facteur principal qui a influencé la distribu- tion latitudinale des assemblages ostracodaux-faunaux; la salinité et la pro- fondeur sont aussi d’importants facteurs de controle: Certaines espéces démon- trent une certaine tolérance envers ces facteurs écologiques, lorsque d’autre espéce sont restreintes dans leurs ambients d’une facon marquée. Comme résultat de cette étude, quelques changements de température sont enregistrés pendant le Cénozolque, et des variations de salinité et de profondeur peuvent s’inférer dans quelques bassins. INTRODUCTION The purpose of the present work is to pursue the two following funda- mental objectives: 1) To establish some ecological factors that influenced the distribution of *The paper was read by R. C. Whatley 318 A. BEeRTELS marine ostracodes during the Upper Cretaceous and Cenozoic, particularly the Tertiary, of Argentina. 2) To show in an approximate integral form the microfaunal assemblages of ostracodes which prevailed during the above mentioned interval and attempt to infer some phylogenetic relations within selected lineages. From recent literature, it is apparent that Recent benthonic ostracodes are, in many cases, very restricted environmentally. Because of this, they can be used to reconstruct palaeoenvironments. In the upper part of the Cenozoic, to approximately as far back as the Oligocene, these reconstructions are relatively easy to make because these deposits contain the same, or very similar taxa as those living in Recent seas. However, in the early Tertiary and Cretaceous these reconstructions are more problematical because the taxa are less closely related to living forms, and it becomes necessary to guess as to their environ- mental limitations. This problem to some extent can be resolved by recourse to the known ecology of other microorganisms. It is intended in this work to demonstrate which microfaunas prevailed during these periods in the Argentine and to show how, with the aid of other tools (such as lithology, Foraminifera, and other microfossils), the ostracodes can be used as chronostratigraphic and palaeoenvironmental indicators. Fre- quently these are the only elements the author had to use, in many parts of the sedimentary basins discussed below. It is not the author’s purpose to make a detailed systematic review of the fossil forms found up to the present day in our country, because it would be outside the scope of the present work. Nevertheless it is necessary to remark that the fundamental factor underlying both ecologic and palaeoecologic studies is an accurate and consistent taxonomy. This problem is not, in this case, so serious because the greater part of the species are new and in most cases I refer to an assemblage of microfossils which typify each of the separate marine stages and because mostly I refer to one type locality within each basin. The data on which this work are based were taken from all the works published to date within this field in the Argentine and also those unpublished theses dealing with the same topic. The mentioned and illustrated material was collected by the author and is deposited at the Facultad de Ciencias Exactas y Naturales, Laboratorio de Micropaleontologia, under the numbers 588 to 657. The author has in most cases followed the taxonomic usages of other workers; however, in certain cases changes have been made, mostly at the generic level, which are indicated in parentheses. ACKNOWLEDGMENTS The author wishes to express gratitude to the Argentine National Council for Scientific and Technical Research, for economical aid in the realization of Pay Cees oe URUGUAY MONTEVIDEO Tare) gavt s v2s2 PROVINCE OF BUENOS AIRES nuejant Y/78 ° 5 MAR DEL PLATA PANES 1245 © BAHIA BLANCA °o Ane ainsi vis eA/vi/23 “ayvino PA/VIAS EAIViin wAlvi/ie eae PROVINCE OF RIO NEGRO BAHIA SAN BLAS SAN ANTONIO OESTE A ce teat eager Ww 93 ALOEZ JUNTA DELGADA eae CHUBUT a Ne | «& PESO. xI/6 | —+— 1] ° GOLFO SAN JORGE CALETA OLIVIA : % | CABO BLANCO zg a a\ PROVINCE OF PUERTO DESEADO 2 7s SANTA CRUZ BAHIA SAN JULIAN BAHIA. GRANDE ! FALKLAND ISLANOS [Matvimas] cicsllie MIO GALLEGO oe STANLEY SIRAITS OF MAGELLAN (Sta GRAWOE Pear AOS EStADOS < = found by us ++ = reported previously substrate remains undisturbed. Population is moreover only possible, if the sand grains are large enough to produce a wide interstitial system. Polycope, and also Cobanocythere and Parvocythere were present here. Cobanocythere and Parvocythere were described by the author from the Pacific Coast of Central America (Hartmann, 1964). Later on they were found by Reys (1961), and Marinov (1962) in the Mediterranean Sarmatian region. We found them in a higher number of species than known until now, and it is probable that they are distributed worldwide in temperate and warm waters. The Poly- copidae found by us belong to two different groups sensu Bunaduce (1964), to the clathrata-group and the loscobanosi-group. All species found at the West Coast belong to the clathrata-group, most species of the East Coast to the loscobanosi-group. Species of the clathrata-group are known, until now, mainly from North Europe and the Mediterranean. Species of the /oscobanosi-group are known, until now, only from the warm and temperate Americas. This group seems to be an Indopacific-West Atlantic element. 2. When we compare the protected beaches of the Humboldt Current and the Benguela Current, we find that many ecological niches are occupied by species of worldwide distributed genera. Only these species form the simi- larity in the biota of these beaches. But there are differences too: Paracytheroma f. ex., frequent in America, is not present in Africa. Species of Loxoconcha and Cytherura replace it. Species of the Bairdiidae play an important role on beaches of the warmer parts of the Benguela Current. They are scarce in the comparable biotypes of the Humboldt Current. Only Cytherois and Procythereis exist in both antiboreal regions. LitrorAL OsTRACODA AFRICA 359 3. Most interesting are the phytal communities of ostracodes. It is also here that the Bairdiidae are characteristic for the Benguela Current, very much less frequent in America. Hemicytheria of South America is replaced by Semicytherura. Thus the similar composition of ostracode populations of both currents is much less than in other animal groups, i.e., Polychaeta and fishes. A difficult problem is the distribution of plant-sucking ostracodes of the genus Paradoxostoma. The phytal communities of the Benguela Current have a very high percentage of species of Paradoxostoma. In earlier papers (Hart- mann-Schréder and Hartmann, 1962, 1965) we pointed out that Paradoxostoma is very scarce in the phytal zone of the Humboldt Current. We do not know whether differences in the chemical composition of the algae-liquors cause this phenomenon. A similar discordance is true for species of Xestoleberis which are very frequent in the algae of the Benguela Current. 4. The composition of the brackish-water communities of ostracodes of both continents is also very different. These biotopes are systematically, by far, richer in America. Perissocytheridea, Paracytheroma, and species of the Thalassocypridini are not present in Africa, when we compare only the West Coast. Cyprideis, a classical element of brackish water, is present at both coasts, but more diverse in America. The Cyprideis species of the African west coast all belong to one closely related group, those from America aie not so uniform. Cyfrideis is not present in the brackish water of the Cape Province. It is completely replaced there by the endemic Sulcostocythere. Cypridets is also missing along the east coast of Africa, as far as our studies indicate. 5. At least we should have a look at the specific ostracode fauna of the coral reefs. Until now all papers on the meiofauna of coral reefs negate the existence of a specifically adapted meiofauna. The opinion prevails that it is the phytal fauna which also populates the coral reefs (v. Gerlach, 1959). Our studies in the coral reef of Tanga lead to another conclusion: other than typical species of the phytal and typical species of the interstitial communities, such as Polycope, Cobanocythere, Microcytherura and some species of Xestole- beris, we found a series of new genera, that we have regarded as representa- tives of ostracodes which to high degree are adapted to the life in coral reefs. Their shell morphology resembles that of the interstitial ostracodes (f. ex. Mesocorallicythere, Hartmann, 1973) or possesses special morphological charac- ters (f. ex. Corallicythere Hartmann, 1973). Typical is the structure of the limbs; we observe the following features: 1. Reduction of bristles and claws, 2. Reinforcement of the remaining claws and bristles, 3. Enlargement of one walking leg (maxilla or one of the two thoracic limbs), 4. Transformation of one or more extremities to a specialized form. Considering these findings, we can be almost sure that the coral reefs harbour not only phytal and interstitial ostracodes, but also a specific coral ostracode fauna. 360 G. HARTMANN AND G. HARTMANN SCHRODER Table 4. Ostracoda from the antiboreal part of the Benguela Current (Luderitzbucht to Kommetje/Simmonstown) 3 =| =) > See 23 e 3 5 $ SG we, Sil (2 ne Rink iaihb es = a vo ° I c ° cS u fe Mee Re Sons Paradoloria dorsoserrata (G. W. Miller, x + + X 1908) Euphilomedes africana (Klie, 1940) x Cylindroleberis grimaldi (Skogsberg, 1920) x + + x + xX sensu Klie, 1940 Cylindroleberis muelleri (Skogsberg, 1920) x Rutiderma cf. compressa Brady & Norman, xX + + + + + x >< 1898 Polycope, n. sp. 1 x Polycope, n. sp. 2 x Bairdia, sp. 44 > aka es a e.4 Cyprideis remanei Klie, 1940 x Aurila, n. sp. 1 autais fede Aurila, n. sp. 2 SZ NSS SR Hemicythere mirabilis (Klie, 1940) x Aurila levetzovi (Klie, 1940) x Mutilus, n. sp. ea SE ee nie ec Procythereis major Klie, 1940 x Procythereis minor Klie, 1940 pests se Procythereis serrata Klie, 1940 x Loxoconcha megapora Benson & Maddocks, x + + x + x 1964, n. subspec. Semicytherura, n. sp. x Xestoleberis baja Klie, 1940 x Xestoleberis crenulata Klie, 1940 x Xestoleberis ferax Klie, 1940 WON SESS Xestoleberis ramosa G. W. Miiller, 1908 SSS SE SS SP OM Sclerochilus incurvatus Klie, 1940 x Cytherois minor G. W. Miiller, 1908 x to Antarctica Paradoxostoma auritum Klie, 1940 x + +++ x Paradoxostoma angustissimum Klie, 1940 x Paradoxostoma caeruleum Klie, 1940 Sa Paradoxostoma griseum Klie, 1940 Sx) a Paradoxostoma reflexum Klie, 1940 x Paradoxostoma semilunare Klie, 1940 MS Paradoxostoma, n. sp. 1 4 ain) sis xX Paradoxostoma, n. sp. 2 SC) cine ain Paradoxostoma, n. sp. 3 Ds Parvocythere, n. sp. 4 x Propontocypris flava G. W. Miller, 1908 ~~ + + ~x Sulcostocythere knysnaensis Benson & Maddocks, 1964 Deg Mi ee Sods Xestoleberis capensis G. W. Miiller, 1908 x Macrocypris africana G. W. Miiller, 1908 x Macrocypris dispar G. W. Miiller, 1908 x Propontocypris gaussi G. W. Miiller, 1908 x xX = found by us + = reported previously LirrorAL OsTRACODA AFRICA 361 Table 5. Ostracoda from the antisubtropical Indic Coast of South Africa (Kap to St. Lucia-Astuar) fe > gz 5 ee As: oe ee = iia NS ae A aan ea a teal ay eS Parvocythere, n. sp. 1 x Parvocythere, n. sp. 2 x Cytherella cf. punctata Benson & Maddocks, 1964 ve ?Bairdoppilata villosa (Brady, 1880) Re Perissocytheridea aestuaria Benson & Maddocks, 1964 Sf Oe eS? Caudites, n. sp. 1 < Procythereis, n. sp. x Cytheretta knysnaensis Benson & Maddocks, 1964 x Loxoconcha parameridionalis Benson & Maddocks, 1964 x N. gen., n. sp. 1 Sa ee KP N. gen., n. sp. 2 x Semicytherura, n. sp. x Aglaiella railbridgensis Benson & Maddocks, 1964 MK Ghardaglaia, n. sp. <4 ot oe Polycope, n. sp. eres Caudites, n. sp. 2 xe —? Tanella, n. sp. x xX—? xX = found by us + = reported previously SUMMARY Summing up, we can give the following statements: il The Humboldt Current and Benguela Current have a slightly different oceanographical zonation. The zonation of faunas is nearly the same in the upper littoral of both currents. The ostracode fauna of both regions is completely different in species, but are similar at the generic level as evidenced by worldwide-distributed genera and some Antarctic elements. The interstitial communities of the sandy beaches are similar in both regions. Their genera seem to be distributed worldwide. The communities of other biotopes show more differences than similarities: many genera are replaced in their ecological niches by other genera. Plant-sucking ostracodes such as Paradoxostoma are scarce in the Humboldt littoral but frequent in the Benguela littoral. Bairdiidae play an important role in the Benguela littoral, at least in the warmer parts of the current; they are not nearly so important in the Humboldt littoral. 362 G. HARTMANN AND G. HARTMANN SCHRODER 4. The Cape of Good Hope is a border between the Atlantic and Indopacific communities of ostracodes as in other groups of animals. 5. There exists a typical coral reef ostracode community. Table 6. Ostracode from the tropical coast of Mozambique and Tanzania (from Lourenco Marques to Mtwara) e tc) | event eealie ole Pie hse egies ong rat E s a n Salo) cme Chae SS pobtiedeiie=auboad Callistocythere, n. sp. x Caudites, n. sp. x INGE Sele nssp: x Thalassocypria, n. sp. x Polycope, n. sp. xX Neonesidea, n. sp.
SS ED PUNTA PARINAS ———— KINCHASA S 5 we es AS a 10 10 = = NOV REDONDO a x 15 ber ae MOCAMEDES on \ 20 2S sess 2 SWAKOPMUND es 25 TALTAL LA SERENA —— tropisch tropisch- subtropisch TAA Antiboreal LA. \NarM kuhl HANH subantarktisch Klimatische Gliederung des Humboldt - und Benquela-Strom-Gebiets Text-figure 1. Climatic zonation of the waters of the Humboldt and Ben- guela Currents, as proposed in this paper. 364 G. HarTMANN ANnp G. HARTMANN SCHRODER ZONIERUNG DER OSTRACODEN-POPULATIONEN antisubtropisch antiboreal POTTERY |disjunkt antisubtropisch ~ = S 2 ) ie) a westafrikanisch pe tropisch CACUACO LUANDA N ul Text-figure 2. Zonation of ostracode populations along the coasts of the southern Africa (Angola, SW-Africa, South Africa, Mocambique, and Tanzania). Numbers refer to degrees of latitude. 365 LitTToRAL OsvRACODA AFRICA ‘Q0UINIFUL IIJEM YSa1F = _N[JUIIIASSEMENS “19}BA [B}SEOD [EsIayUI YystyoRsq ‘suv = JasseMpunIsuasNy SaBryoeriq ‘sautieu ‘vas = Jaa ‘aul Jayem Yysty a[pPIAL = MHLW ‘y9F89q Jans = sueyl[eid ‘JJM [BYSI9JUL axe} 0} a[oOY = YOo[Jassempunigy ‘pues Jstour Fo suN0z = auozpuesjyonag ‘yovaq Apues = puesjspurg) yovaq [eoido1} B FO WOIIIS "§ FINDBIF-}X9 T, ° Cfo OMB? ars oy Oo ° ° ° ° ° ° © 06 OS Oi ° o ° ° ° ° ° ° ° YSSSVMGNNYONSLSNY: . wale Me 7? ae : 2 r ie ac . a . . 26 on . . . ° fe} ° ° ° ° ° ° ° ° ° ° Gato Ag Sin Deny conUe a ‘ io ¥ 3 ° ° ° ° ° of .s?* ahnhe cage © S, . aifec-, . . . 2 SSIES Bs oC eT RY ARON SU Senn eT a : . . . ° o G8 0o (O)aO) peer" tio ° SRO SOC rn CEG Op DEC RON OT Sea a AMER RLAL siete s: cio ° of. ae . toe ait) Sexe . 5 © o eSA9IMOVYE POLO Gas a ocks 0c he UASSVMSSNS ° , eee ite teen TOININV Wes 09 a o 8 Cy Cys CI aC) Cao oh OOO” CRC HR GIO CUT eO et) O80 SORA ON CECA sii Ce Ole* 0 o (0798 6 ° OG Oe a TON ORY, CC AO ut FeO DOGO OR, peed * . . oe ° ° ° ° ° ° LOG ATANOAR oe ence Sishe seh eie ties ol GR Oey ee 8 of ° ° /; Wee how AOR tata Wie 11/17 1 BONES ony Wed Uf TL by Ligietined SEAS ONVULSONVS SN HOO 1Y3SSVMGNNY9 N3dOYL NAC NI WSOY¥dONVULS YSSn 366 G. HarTMANN AND G. HARTMANN SCHRODER REFERENCES Bate, R. H. 1971. The distribution of Recent Ostracoda in the Dhabi Lagoon, Persian Gulf. Paléoécologie des Ostracodes, Colloque Pau (1970). Bull. Centre Rech. Pau SNPA 5: 239-256, 3 figs., 3 pls. Editor: H. Oertli. Benson, R. H., and Maddocks, R. F. 1964. Recent Ostracodes of Knysna Estuary, Cape Province, Union of South Africa. Univ. Kansas Paleont. Contr., Arthropoda Art. 5, pp. 1-39, pls. 1-6, figs. 1-22. Bold, W. A., van den 1966. Les Ostracodes du Néogéne du Gabon. Revue Inst. Frang. Pétrole XXI, 2, pp. 155-188, 6 planches, 1 map. Bonaduce, Gioacchino 1964. Contributo alla conoscenza e correlazione sistematica nell ambito della Famiglia Polycopidae (Ostracoda, Cladocopa) con particolare riferimento alle relazioni tra parte molle e carapace, Pubbl. staz. zool. Napoli, 34, pp. 137-159. Brady, G. S. 1880. Challenger Report. Ostracoda. Zoology, 1, 3, pp. 1-184, pls. 1-44. Gerlach, S. A. 1959. Uber das tropische Korallenriff als Lebensraum. Verhandl. Deutsche Zool. Gesellschaft, 1959, 4 Abbild., pp. 356-363. Grekoff, N. 1958. Ostracodes du Bassin du Congo, III, Tertiaire. Mus. Roy. Congo Belge, Ann. Sci. geol., ser 8, vol. 22, pp. 1-36, pls. 1-3. Hartmann, G. 1953. Iliocythere meyer-abichi n. sp., ein neuer Ostracode des Schlick- wattes von San Salvador. Zool. Anz., 151, 11-12, pp. 310-316, Text- figs. 1-17. 1956. Zur Kenntnis des Mangrove-Estero-Gebicts von El Salvador und seiner Ostracodenfauna I. Kieler Meeresforschungen, 12, 2, pp. 219-248, Tafel 30-32. 1957. Idem., Teil Il. Ibid, 13, 1, pp. 134-159, Tafel 39-50. 1959. Zur Kenntnis der lotischen Lebensbereiche der pazifischen Kiiste von El Salvador unter besonderer Beriicksichtigung seiner Ostra- codenfauna. Kieler Meeresforschungen, 15, 2, pp. 187-241, Tafel 27-48. 1964. Zur Kenntnis der Ostracoden des Roten Meeres. Ibid. Sonderheft 20, pp. 35-127, 62 Tafeln. Hartmann-Schroder, G., and Hartmann, G. 1962. Zur Kenntnis des Eulitorals der chilenischen Pazifikkiiste und der Kiiste Siidpatagoniens — unter besonderer Beriicksichtigung der Polychaeten und Ostracoden, Mitt. Hamburg Mus. Inst., Ergan- zungsband 60, pp. 1-270, Textfiguren, Tabellen, Karten. 1965. Zur Kenntnis des Sublitorals der chilenischen Kiiste unter be- sonderer Beriicksichtigung der Polychaeten und Ostracoden (mit Bemerkungen iiber den Einflu8 sauerstoffarmer Strémungen auf die Besiedlung von marinen Sedimenten. Ibid., Erganzungsband 62, pp 1-384, Textfiguren, Tabellen, Karten. Klie, W. 1940. Beitrage zur Fauna des Eulitorals von Deutsch-Siidwest-A frika II. Ostracoden von der Kiiste Deutsch-Siidwest-Afrikas. Kieler Meeresforschungen, III, 2, pp. 404-448, 91 Abb., Tabellen. LirroraAL OstTrRAcoDA AFRICA 367 Krommelbein, K. 1965. Ostracoden aus der nicht-marinen Unterkreide (“W estafrikanischer Wealden”) des Kongo-Kiistenbereichs, Meyniana, 15, pp. 59-74, 4 Tafeln, 1 Abb. 1966. On “Gondwana Wealden’. Ostracoda from NE Brazil and West Africa. Proc. 2nd W. African Micropal. Coll. (Ibadan, 1965), pp. 119-123, figs. la-3c. Marinov, T. 1962. Uber die Muschelkrebs-Fauna des westlichen Schwarzmeer- strandes. Bull Inst. Central de Recherche scientifique des piscicul- ture et de pécheries, Varna, Acad. Bulgarie Sciences, II, pp. 81- 108, 10 Tafeln. Miller, G. W. 1908. Die Ostracoden der Deutschen Siidpolar-Expedition 1901-1903, im Auftrag des Reichsamtes des Inneren herausgegeben von E. wv. Drygalski. X, Zoologie, Heft II, pp. 51-181, Tafel 4-19, Textfiguren. Omatsola, M. E. 1970. On occurence of cytherellids (Ostr. Crust.) in a brackish-water environment. Bull. Geol. Inst. Univ. Uppsala, n.s. II, 10, pp. 91-96, Dlaglh fisse3ei( Bubli Now 99) 1970. Notes on three new species of Ostracoda from the Niger Delta. Ibid. V1, 11, pp. 97-102 (Publ. No. 98). 1971. Podocopid Ostracoda from the Lagos Lagoon, Nigeria. Micro- paleontology, 16, 4, pp. 407-445, pls. 1-13. Poulsen, E. M. 1962. Ostracoda-Myodocopida, part I (Cypridiniformes-Cypridinidae). Dana-Report, 57, pp. 5-413, 181 figs., 26 tables. 1965. Pt. II: Rutidermatidae, Sarsiellidae, Cylindroleberididae. Ibid., 65, pp. 1-483, 156 figs. 1969. Pt. IIA: Halocypriformes-Thaumatocyprididae and Halocypri- didae. Ibid., 75, pp. 5-100, 40 figs., 19 tables. Reyment, R. A. 1959. Die Gattung Paijenborchellina im Unter-Eozdn Nigeriens. Contr. Geol. Stockholm Univ., 3, 7, pp. 139-143, pls. 1-2. 1960. Studies on Upper Cretaceous and Lower Tertiary Ostracoda. Pt. 1: Senonian and Maestrichtian Ostracoda. Ibid., 7, pp. 1-238, 23 pls., 71 figs. 1960. Pt. 2: Danian, Paleocene, and Eocene Ostracoda. Ibid., 10, pp. 1-286, 23 pls., 81 figs., 1 Tab. 1960. Pt. 3: Stratigraphical, paleoecological and biometrical conclusions. Tbid., 14, pp. 2-143. Reyment, R. A., and Reyment, E. 1959. Bairdia ilaroensis n. sp. aus dem Paleozdn Nigeriens und die Giiltigkeit der Gattung Bairdoppilata (Ostr. Crust.) Ibid., 3, 2, pp. 59-67, pl. 1, text-figs. 1-5. Reys, S. 1961. Recherches sur la systematique et la distribution des ostracodes de la region de Marseille. Rec. Trav. St. Mar. Endoume, Bull. 22, 36, pp. 53-109, 10 Tafeln, Tabellen. Gerd Hartmann and G. Hartmann-Schréder, Zoologisches Institut and Museum, 2 Hamburg, Germany. 368 G. HARTMANN AND G. HARTMANN SCHRODER DISCUSSION Dr. I. G. Sohn: I would like to compliment Dr. Hartmann for his meticulous bookkeeping. More than once I have needled many of my colleagues to cite the author and date of each species. Otherwise, it is sometimes impossible to know which taxon is discussed. Dr. Hartmann’s slides are excellent examples of identifying each species by author and date, and that, I think, is the proper way of doing it. Dr. R. C. Whatley: I would like to congratulate Dr. Hartmann on a really fundamental and beautifully presented paper. I think he’s given us ail a very clear idea on what’s going on. I’d just like to make one small point. I think you probably knew I was going to make it. As a result of more detailed sampling, I demonstrated, for example, at least Callistocythere dispersocostata is not disjunct and it goes right the way round, I got it living going right down at almost all my little stations. And also I found it in Puerto Montt. I don’t really know how far it goes up. In my paper with Moguilevsky we cite its occur- rence living as far south as the Beagle Channel and I have recently recorded it, also living, at Puerto Natales in Southern Chile. In addition, it occurs not uncommonly in the Southern Patagonian and Fuegian littoral. Dr. Hartmann: That’s very interesting. Dr. Hazel: I missed what you said. At what depth did sampling stop on the West African Coast. Dr. Hartmann: Upper littoral, to a depth of 2 meters I’d say. We sampled from the shore outward. Dr. Hazel: Did you have relatively consistent diversity or was it very erratic? Dr. Hartman: Oh no. We could find the different species always along the coast, the climatic zones had their special ostracode fauna. It is possible that some of the northern forms occur in deeper water in the south, but we sampled from shore because most of the work was done up to now from ships. Dr. Hazel: Were you able to determine that distributional limits in some species were being controlled by winter temperatures and others by summer tempera- tures? Dr. Hartmann: We did only one sampling. We have to go on to sample in other seasons at our stations. We tried only to find the boundaries more or less. We have to make more exact studies of the life cycles. Dr. Kornicker: I’d like to know if you found any species present both along the South American coast, either side, and also the African coast? Were there any similar species? Dr. Hartmann: Oh yes. Cyftherois minor. This occurs also in Africa. That’s the only one. Dr. Loffler: Are there any relationships of your assemblages to those of the Antarctic ? Dr. Hartmann: I would say that between South America and the Antarctic there would exist a close relationship but less between Africa and the Antarctic. Dr. Benson: What do you think are the affinities of Sulcostocythere? Dr. Hartmann: The soft parts are very close to what you called Cytheridae. Sulcostocythere belongs to the Cytheridae. I place it in a tribe: Schistocytherini. The soft parts are close to Cythere s.s. The same is true for Schizocythere as Hanai showed. A PRELIMINARY SURVEY OF THE OSTRACODES OF HALIFAX INLET Q. A. Sippigui aANp U. M. Grice Saint Mary’s University ABSTRACT The marine and brackish-water ostracode fauna of Nova Scotia, hitherto little known, is now being investigated. The area is described, with special reference to Halifax Inlet on the Atlantic Coast, where the investigation was begun. Two ostracode assemblages are recognized: (1) Littoral assemblage typi- fied by Cytherura elongata Edwards, 1944, and (2) Sublittoral assemblage in which Xestoleberis sp., Baffinicythere emarginata (Sars, 1865), Paradoxo- stoma variabile (Baird, 1835), Sclerochilus contortus (Norman, 1861), Muel- lerina canadensis (Brady, 1870), Cythere lutea Miller, 1785, and Hemicythere villosa (Sars, 1865) occur most commonly. DES OSTRACODES RECENTS DE LA CRIQUE DE HALIFAX NOVA SCOTIA, CANADA RESUME Des Ostracodes sont en train d’étre receuillis des eaus prés du bord de la mer et du plateau continental de Nova Scotia, avec une concentration actuelle- ment sur la faune de la Crique de Halifax. Des informations sur la taxonomie, la distribution locale, et l’écologie des espéce receuillies, et des illustrations sont aussi en train d’étre compilées. Le travail actuel exposera les résultats de ces investigations jusqu’ici. INTRODUCTION This investigation was planned as a pilot study for a survey of the marine and brackish-water ostracodes of the Nova Scotia coast. Little work has been done in the region; the nearest and latest was published by Hazel (1970), on samples collected by United States vessels from off the coast of eastern North America. Hazel summarised previous research and also discussed the question of faunal provinces. The present authors have adopted his delimitation of the Nova Scotian faunal province as extending roughly from Cape Cod, Mass., U.S.A., to Cape Race, Newfoundland, Canada. Nova Scotia is a focal point for research in oceanography and oil prospecting, centered upon the cities of Halifax and Dartmouth, so that access to certain facilities is assured. The province of Nova Scotia is a peninsula joined to the Canadian main- land by the low and marshy Isthmus of Chignecto. Its long axis lies roughly northeast to southwest, parallel to the mainland coast. It slopes down towards the Atlantic Ocean and also dips to the southwest, the highest hills being in the Cape Breton Highlands and the lowest land mainly around Shelburne. The sea coast of Nova Scotia can be divided into three regions. The first is the northwest coast, along the Nova Scotia shores of the Bay of Fundy, from Brier Island to the New Brunswick border. This coast is subject to a very large tidal range, a heavy load of suspended sediment and extensive mud- flats at low tide; there is relatively little exchange of water with the seas outside. The second is the Gulf Shore, along the margin of the Gulf of St. 370 Q. A. Sippigur anp U. M. Grice Gulf of St. Lawrence New Brunswick oe Halifax Inlet Nova Scotia aXe or pe 50 0 50 100 km Text-figure 1. Map of Nova Scotia coast, showing position of Halifax Inlet. Lawrence; much of this is sheltered from the main circulation of the Gulf by Prince Edward Island which forms the other boundary of Northumberland Strait. It is thought by some workers that there was a strait through the present Isthmus of Chignecto, and an isthmus between Caribou, Nova Scotia, and Wood Island, P.E.I., during at least one interglacial period. During this time ele- ments of the Virginian Fauna may have reached the Gulf of St. Lawrence through the sheltered Bay of Fundy, accounting for certain species found to- day in some areas with high summer temperatures, for example, Crassostrea virginica (Gmelin) in P.E.I. Finally, there is the Atlantic Coast including the northeast and southwest shores. This coast is subject to extensive wave action, and exposed to oceanic currents. The Atlantic Coast is much incut, and scoured by ice, forming long inlets, many of them protected from the ocean by the local topography and by barrier beaches. Thus they provide sheltered habitats with varying salinity, and extensive marshes which, like the shores on the other coasts, are fre- quented by water birds, especially during migration. The deepest inlet is Halifax Inlet, which has been used as a harbour for trade and defense for over two hundred years. OstracopEs HALIFAX INLET 371 HA.IFax INLET Halifax Inlet is about 25 km long and trends from northwest to southeast, following the preglacial course of the Sackville River, now deepened by ice. The innermost part, Bedford Basin, is practically landlocked, and has a central deep which descends to 75 metres, the deepest part of the Inlet. Bedford Basin is connected to Halifax Harbour by the Narrows, a channel constricted by Halifax Peninsula jutting out into the inlet and which has a rock sill at 20 m depth. Halifax Harbour is the longest part of the inlet and is navigable over most of its area, with the main channel on the west side and always at least 23 m deep. An arm of the sea, the Northwest Arm, runs up from the seaward end of Halifax Harbour dividing the Halifax Peninsula from the mainland to the west: this also is navigable for some distance. Last comes the Seaward Approaches, opening to the ocean between Hart- len Point and Chebucto Head. Cow Bay, a marshy inlet east of Hartlen Point, was included in the study area when the extent of the pollution of Halifax Inlet became apparent. The district has a temperate and foggy climate with a mean annual temperature of 44°F: most of Halifax Inlet remains ice-free all winter. Pre- cipitation averages 50” a year, about 5” of it in the form of snow. The largest fresh-water inflow is from the Sackville River which empties into the head of Bedford Basin, and discharges as little as 0.25m%/sec. in the dry season and as much as 86m?/sec. after Hurricane Beth in 1970. There is a certain amount of land drainage and runoff from inland lakes, some of it controlled by weirs. It is estimated that the volume of fresh-water inflow into Halifax Inlet may be equalled during most of the year by domestic and industrial waste waters. There is settlement round most of the margin, heavily concentrated in Halifax on the west, with most of the docks, and Dartmouth on the east with less. More than 50 industrial sewers are reported to open into Halifax Harbour in the 5 km occupied by Halifax docks. The main sewer from residential Halifax opens into the Northwest Arm at its seaward end, whence its effluent is swept out to sea along the bottom quite effectively (Stanley 1968). Hydrographic conditions are fairly stable; salinities are not much less than that of seawater, and freshwater is not found near the bottom except at the mouths of streams. Surface waters are seldom less saline than 29 o/oo, and bottom waters in the deepest parts have salinities of 31-32 o/oo. Stratification occurs in summer; inversion is unusual but has been known to occur. Oxygen concentrations are reported to be almost always high. Considering this harbour’s long history it is surprising to find that its current system is not well understood. The Bedford Institute has recently completed a survey of salinity, temperature, and density of the water along eight survey lines traversing the inlet from Bedford Basin to the outer ap- proaches. Thirty-one stations were visited monthly for over a year. The data were published without comment in July, 1972 and have not yet been assimilated (Jordan, 1972). Bottom water enters Halifax Inlet along its eastern side, and flows out on the west; the offshore current sets southwestward parallel to the Sie Q. A. Sippigur anp U. M. Grice Sackville River Bedford Bay Mill Cove Bedford Basin Wright's Cove Halifax Inlet [a SES es 2000 0 2000 metres 10m. isobath The Narrows 70m. isobath Halifax Northwest Arm Cow Bay ee Hartlen Osborne xe Poin =o hanes ’ - e ’ % O = ¢ ‘ - Chebucto Head i i i indicated by -fi 2. Map of Halifax Inlet. Collecting stations are inc d ee eee those a lines A-H are Bedford Institute hydrographic stations. Areas with small dots appear to be devoid of ostracodes. OstracopEs HALIFAX INLET 373 coast. Flushing out must be fairly effective since little garbage is thrown up on shore, but there are places where few organisms can live, and the state of Bedford Basin is causing concern. Bottom deposits vary from muds at the landward end of the Inlet to boulders, sands and gravels at the mouth, with scoured rock in some places such as the Narrows. The muds are often sticky and foetid, supporting a limited fauna, all of it at the mud/water interface. Exploratory collections were made in 1970-72 around the shores of Bedford Basin, the Northwest Arm, and Cow Bay, and from a launch in various parts of the Inlet. In June 1971 collections were made on several of Bedford Insti- tute’s hydrographic stations. All the hydrographic stations were run again in the spring of 1972, except for some on the A and B lines, which could not be worked because of rough weather. It was thought that the correlation of the STD data with the results of sample analysis for ostracodes would be useful although the STD apparatus stopped 3 m short of the bottom. Some of the material collected by Murray Gregory for his thesis on the Foraminifera of Halifax Harbour has also been examined for ostracodes. Collecting methods at sea involved use of an Eckman grab with a 36 sq. in. sampling area and a modified Forster anchor dredge with an adjustable bite. Material was sieved through a series of steel sieves: mesh sizes used were 0.25 mm and 0.125 mm. A 1/4” mesh garden sieve was sometimes used to screen out coarse material, and the finest sieve was omitted for samples of sticky mud. Sieving was carried out on the spot, and material was sorted fresh if possible and stored in 70% isopropyl alcohol. Shore collections were treated the same way at first, samples of the substratum being sieved and sorted; recently methods have been changed to the sorting of material skimmed in small quantities from the substratum with dipnets lined with nylon hoisery mesh; weed washings are also examined. Ostracodes collected this way survive the journey back to the laboratory well and can be cultured or dissected. Two species from brackish water have been cultured successfully so far. Cytherura elongata has gone through two generations in six weeks, the whole adult population breeding together and then dying, while an unidentified species is breeding in the laboratory, but not synchronously, and the adults have survived reproduction. Cytherura elongata feeds on algae, while the other species is thriving on a suspension of baking yeast. Current preoccupation is with the collation of data giving the geographical distribution of local species, with reference also to the physical environment, and association with other organisms. A start has been made on investigating and illustrating some common species. There are a few collections on hand from other parts of the province, and the investigation will be extended as soon as possible. OSTRACODE FAUNA The ostracode fauna in Halifax Inlet can conveniently be divided into two assemblages, namely littoral and sublittoral. 374 Q. A. Srppigur anv U. M. Grice LitroraAL ASSEMBLAGE These species occur in Mill Cove and some areas of Bedford Basin, Wrights Cove, and Cow Bay. The water is usually brackish in these localities with measured salinities ranging from 28°/oo to less than 1°/oo in spring. PopocoPa Campylocythere? sp. Cytherois fischeri (Sars, 1866) Cytheromorpha curta Edwards, 1944 Cytherura elongata Edwards, 1944 Hirschmannia viridis (Miller, 1785) Leptocythere sp. Semicytherura nigrescens (Baird, 1838) Myopocopa Parasterope pollex Kornicker, 1967 Sarsiella cf. S. zostericola Cushman, 1906 The most common ostracode in the assemblage is Cytherura elongata fol- lowed by Leptocythere sp., Cytherois fischeri and Cytheromorpha curta. The occurrence of the genus Hirschmannia is of particular interest because this genus so far has not been reported from North America (Van Morkhoven, vol. II, p. 401). The myodocopid ostracodes Parasterope pollex and Sarsiella cf. S. zosteri- cola have been found in eelgrass beds in lagoons at Hartlen Point and Cow Bay, extending the range of these genera northwards. (Kornicker, pers. comm.) SUBLITTORAL ASSEMBLAGE This is a truly marine assemblage occurring in water of salinity greater than 29°/oo (Jordan, 1972). These species are found mainly in the Harbour and towards the seaward side of the Inlet. We have not found any ostracodes in the deeper part of the Basin. This assemblage includes: Actinocythereis dawsoni (Brady, 1870) Baffinicythere emarginata (Sars, 1865) Baffinicythere howei Hazel, 1967 Bensonocythere americana Hazel, 1967 Bensonocythere sp. Cythere lutea Miller, 1785 Cytheretta edwardsi (Cushman, 1906) Cytheropteron sp. Cytherura? mainensis Hazel and Valentine, 1969 Cytherura? undata Sars, 1866 Elofsonella concinna (Jones, 1857) OstracopEs HaLiFAx INLET 375 Eucythere declivis (Norman, 1865) Eucytheridea bradij (Norman, 1864) Finmarchinella finmarchica (Sars, 1865) Hemicythere villosa (Sars, 1865) Hemicytherura clathrata (Sars, 1866) Loxoconcha sp. Microcytherura sp. Muellerina canadensis (Brady, 1870) Munseyella mananensis Hazel and Valentine, 1969 Normanicythere leioderma (Norman, 1869) Palmenella limicola (Norman, 1863) Paradoxostoma variabile (Baird, 1835) Robertsonites tuberculata (Sars, 1865) Sahnia faveolata (Brady, 1880) Sclerochilus contortus (Norman, 1861) Xestoleberis sp. The species which occur most commonly are Xestoleberis sp., Baffincythere emarginata, Paradoxostoma variabile, Sclerochilus contortus, Muellerina cana- densis, Cythere lutea, and Hemicythere villosa. ACKNOWLEDGMENTS The research is financed by grants from the National Research Council of Canada and St. Mary’s University. The authors wish to thank their assistants, Valerie Scholey, Bob Grantham, and Jon Walker, and to acknowledge the help of many colleagues, especially Dr. Francis Jordan of Bedford Institute, Dr. Franco Medioli of Dalhousie University, and Dr. Murray Gregory, now at the University of Auckland. REFERENCES Gregory, M. R. 1971. Distribution of benthonic Foraminifera in Halifax Harbour, Nova Scotia. Ph.D. thesis, Dalhousie University. Hazel, J. E. 1970. Ostracode zoogeography in the southern Nova Scotian and northern Virginian Faunal Provinces. U.S. Geol. Sur., Prof. Paper 529-E, pp. V, E 21, 69 pls. Jordan, F. 1972. Oceanographic data of Halifax Inlet. Unpublished manuscript. Stanley, D. J. 1968. Reworking of glacial sediments in the North West Arm, a fiord- like inlet on the southeast coast of Nova Scotia. Jour. Sed. Petrol., 38, pp. 1224-1241. Q. A. Siddiqui and U. M. Grigg, Saint Mary’s University, Halifax, Nova Scotia, Canada. 376 Q. A. Sippigur anp U. M. Grice DISCUSSION Hartmann: What is the percentage of American and European species in the samples? Siddiqui and Grigg: Of the 36 species definitely identified, 19, or 52.8 percent, are also found in Europe. EXPLANATION OF PLATE 1 All figures except 8 and 11 are scanning electron micrographs. Littoral Assemblage Figure 1. Campylocythere ? sp. External view, right valve; X 38. Cytherots fischeri (Sars 1866). Right view, carapace; X 46. Cytheromorpha curta Edwards 1944. Right view, carapace, female; X 43. 2 3 4. Cytherura elongata Edwards 1944. Right valve, male; X 41. 5. Hirschmannia viridis (Miller 1785). Right view, carapace, male; X 46. 6. Leptocythere sp. Right view, carapace; X 48. 7 Semicytherura nigrescens (Baird 1838). Right view, carapace, female; x 43. 8. Sarsiella cf. S. zostericola Cushman 1906. Carapace open with animal, subadult male; xX 18. Sublittoral Assemblage 9. Actinocythereis dawsoni (Brady 1870). Left view, carapace, male; x 37. 10. Baffinicythere emarginata (Sars 1865). Left view, carapace, female; x 44. 11. Baffinicythere howei Hazel 1967. Right view, carapace, male; X 49. 12. Bensonocythere americana Hazel 1967. Right view, carapace, male; X 37. 13. Bensonocythere sp. External view, right valve, male; X 36. 14. Cytheretta edwardsi (Cushman 1906). External view, right valve, male; x 44, 15. Cythere lutea Miller 1785. External view, left valve; 40. 16. Cytheropteron sp. External view, left valve; xX 40. Plate 1 OstTrRAcopEs HALIFAX INLET 378 Q. A. Sippigur aus U. M. Grice EXPLANATION OF PLATE 2 All figures are scanning electron micrographs. Sublittoral Assemblage (continued) Figure 1. Cytherura? mainensis Hazel and Valentine 1969. Right view, carapace; << Se) 2. Cytherura? undata Sars 1866. External view, left valve, male; X 36. 3. Elofsonella concinna (Jones 1857). External view, right valve, male; X 40. 4. Eucythere declivis (Norman 1865). Right view, carapace; X 39. 5. Eucytheridea bradii (Norman 1864). Internal view, left valve; X 39. 6. Finmarchinella finmarchica (Sars 1865). Left view, carapace, female; Text-figure 1. The Barents Sea. Current directions, mean ice margins from April to August and Arctic/Boreal benthos boundary of Filatova (1957). (After Zenkevitch.) and Brady and Norman (1889) gave records for Spitzbergen. The latter faunas have also been detailed by Miiller (1931) and Klie (1942). To the South, Akatova (1957) has noted a number of White Sea species and Norman (1891, 1902) dealt with the northern Norway faunas in more detail. Elofson (1941) adds some new records for the area generally, especially for Bear Island and Jan Mayen. In the west, material from Greenland and the Baffin Island area was examined in the last century by Brady (1868, 1878) and Norman (1877) and in this century Stephensen (1913, 1936) has published compilations for the Greenland region. More recently Hazel (1970) has examined faunas from eight samples from Greenland Seas and nine from the Canadian area north of 60°N. There are no estimates or details of abundance in the literature except for Klie’s work (1942) in Spitzbergen and Hazel’s work (1970) which gives an indication of the abundance of species in general- ised terms. In this lies the significance of the principal fauna covered here. The present sample contained 4004 ostracodes none of which showed soft parts. It is, strictly speaking, a thanatocoenose, but its dissimilarity to the known Pleistocene faunas of the region, and its similarity to the biocoenoses 384 J. W. NEALE anv H. V. Howe of Greenland and Spitzbergen give no reason for supposing that it is not typical of the biocoenose. One of the principal problems which cannot be stressed too often is the importance of accurate taxonomy. At the 1963 Naples Symposium one of the authors (Neale, 1965, p. 258) stated “In studies of ecology and distribution accurate synonymy is a sine qua non, and in this respect the species is the most significant and important unit”. These sentiments were reiterated by the other author (Howe, 1969, p. 3) at the 1967 Hull Symposium. Both authors would once again stress this aspect of ecological studies. In the present study considerable taxonomic problems have arisen. Formal taxonomic descriptions have, quite rightly, no place in this Symposium and so the new taxa are not dealt with here but are covered elsewhere. Publica- tions dealing with these are listed in the references at the back. Nevertheless, it is necessary to draw attention to a number of taxonomic aspects in passing, particularly to the two principal problems which concern the genera Finmar- chinella and Cytheropteron. The problem of Eucytheridea has already been dealt with by van den Bold (1961). In the case of Finmarchinella, F. finmarchica (Sars) appears to have been correctly interpreted in the literature, the species being clear cut and raising no problems. It is widely distributed in northern seas extending as far south as Brittany. Occurrences in the Bay of Biscay are now thought to belong to the palaeothanatocoenese. (Moyes and Peypouquet, 1971; Peypouquet, 1971). On the other hand, Finmarchinella angulata (Sars) has suffered from confusion, even in Recent times, being confused with two other species, Finmar- chinella barentzovoensis (Mandelstam) and F. curvicosta Neale. Material sup- plied by the Zoologisk Museum in Oslo and labelled by Sars has established the correct interpretation of F. angulata, and the new species F. curvicosta has been based on the excellent material collected by H.M.S. Valorous at Holsteinsborg Harbour, Greenland, in 1875 (Neale, 1974). This latter species is very characteristic of Arctic waters. The same is true of Mandelstam’s species Finmarchinella barentzovoensis for which Russian Harbour is the type locality, and which is also found in west and northwest Greenland (Text-fig. 2). The genus Cytheropteron is in an even more confused state and is difficult to deal with. Abundant material, however, has made the task much easier and Neale and Howe (1973) have established three new species namely C. arcti- cum, C. nodosoalatum, and C. dimlingtonensis. The first two are characteristical- ly developed at Russian Harbour. The last occurs in the Pleistocene at Dimling- ton, East Yorkshire, and in englacial material at Spitzbergen. Comparison with material from Norman’s type locality — probably the type material itself — shows that C. dimlingtonensis is related to, but distinct from, C. latissimum (Norman) with which it has hitherto been confused, and the same is true of C. paralatissimum Swain which is also found at Russian Harbour and widely in Arctic seas. One small Cytheropteron has been left under open nomenclature. It is difficult to interpret with confidence but seems related to C. nodosum Brady on the one hand and an undescribed species from the Pleistocene of Alaska on the other. One species each of Cytherois and Semicytherura believed Hicu LatTirupE MARINE OsTRACODA 385 @ Rabilimis septentrionalis (Brady) 4 Finmarchinella barentzovoensis (Mandelstam) TENITHAL EQUAL AREA Text-figure 2. Distribution of Rabilimis septentrionalis (Brady) and Finmarchinella barentzovoensis (Mandelstam). to be new have been left under open nomenclature for the present, as have three single valves, two of them very small, belonging to three distinct species. The material used in this study has been named at the specific level and counted so as to give some information on abundance which may be used in com- parison. However, before considering the fauna in more detail a number of remarks must be made about the techniques used and some of their relative advantages and disadvantages. After completing the taxonomic determinations two approaches are possible in determining the affinity of any particular fauna with others, namely the qualitative presence/absence method and the quantita- tive composition of the fauna method. Both have certain advantages and dis- advantages and both have been used in this study. From our previous remarks it is clear that for any meaningful results both depend on accurate taxonomy. The qualitative method depends simply on comparison of species present or absent in individual localities. It has the advantage that it is fairly quick and that use can often be made of previous work although in the latter case the taxonomy must usually be taken on trust. It suffers from the fact that rare species are given as much weight as common species and may thus unbalance any comparisons made unless some form of weighting or arbitrary restriction is introduced. Further refinements may be made, and by the use of computers 386 J. W. Neate anv H. V. Howe vast amounts of data can be processed quickly and comparison charts printed out, always with the proviso about the effect of rare species and the taxonomic determinations mentioned above. Using quantitative methods gives information on the abundance of various species, rare species are not overstressed and to this extent the results are more meaningful than simple presence/absence data. It means, however, that the method is time consuming, data from other workers are rarely in usable form and the work needs to be rigidly controlled and self-consistent. The re- sults may be expressed by a number of methods such as histograms, fence diagrams, pie diagrams etc., but the value of easy comparison by these methods falls off after the number of localities or samples compared reaches a certain size after which other techniques are better employed. Ideally the data should be self consistent and uniform as regards collection, processing and taxonomy and below we examine how far the present study is satisfactory in this respect. 1. Collection As this was not a specially funded research programme, the study was dependent on the material readily available. This consisted of material brought up at Russian Harbour by the sounding lead, material from the sta- tions occupied by H.M.S. Vidal and the Ernest Holt and brought up by conical dredge, and Museum material. Because the work was not based on uniform weights or volumes, the samples present no problems except for the Museum material about which there are reservations as given below. 2. Processing In the case of most of the samples this was under the direct control of the authors and all material held on a B.S.S. 100 sieve was picked and counted. The choice of sieve represented a compromise between obtaining a representa- tive fauna in a reasonable time on the one hand, and losing the early instars on the other. Because this was consistent for all the samples except those detailed below this raises no problem. It is a problem, however, in the case of the three Museum samples from Greenland and Franz Joseph Land and the Spitzbergen sample taken from the literature. There is no certainty that this was processed on a sieve of similar size, but the value of at least some roughly comparable data from Greenland and Spitzbergen was thought to outweigh any possible lack of consistency. Again, whilst the whole of the available Museum material was examined and counted, there is no guarantee that this was the full fauna recovered, but again provided that this is borne in mind, some comparison seemed better than none. 3. Taxonomy With the single exception of the Spitzbergen Station 6 of Romer and Schaudinn, data for which were taken from Klie (1942), all the specimens used in the quantitative work were examined by the authors personally. 4. Size of sample Being dependent on what material happened to be available, all specimens were counted and no restriction imposed on size because in this sort of work Hicu LatirupE MarINnE OsTRACODA 387 the more specimens available the more accurately the resulting percentages re- flect the actual occurrence of the species. It is generally held that 300 specimens form an acceptable minimum for this type of work. In the present case the Spitzbergen Shelf Sample 46 (176 specimens), Dimlington (251), the Museum Greenland samples (127, 233) and Romer and Schaudinn’s Spitzbergen Station 6 (74) fall short of this but interest was thought to justify their inclusion. From this one may conclude that with the exception of the Museum samples and the Spitzbergen data from Klie (1942) which should be treated with circumspection, the other data which were under the direct control of the authors are reasonably self-consistent. THE RUSSIAN HARBOUR FAUNA The fauna is dominated by trachyleberids, hemicytherids, and the genus Eucytheridea and the details are given in Table 1. Altogether 45 species are present of which Robertsonites tuberculata (Sars), Baffinicythere howei Hazel, B. emarginata (Sars), Eucytheridea punctillata (Brady), and E. macrolaminata (Elofson) make up more than half the total population. With the addition of Finmarchinella barentzovoensis (Mandelstam), Cytheropteron paralatissimum Swain, Semicytherura undata (Sars), Normanicythere leioderma (Norman), Cytheropteron nodosoalatum Neale and Howe, and Acanthocythereis dunelmen- sis (Norman) these 11 species account for over three-quarters of the total population. Robertsonites tuberculata (Sars), the commonest form, is a well-known trachyleberidinid component of shallow water boreal and Arctic faunas and prefers the sublittoral, reaching its maximum abundance at depths of less than 50 fathoms. It is found round the British Isles and has been found by one of the authors in a Recent study of the Celtic Sea where it occurs in 44% of the samples from the Cockburn Bank (ca. 49°45’N, 9°20’W) where it may make up to 6% of the fauna. Here it has been interpreted as being at about the southern limit of its range. It occurs farther to the south in the Bay of Biscay where it has been interpreted by Peypouquet (1971) as part of a palaeothanatocoenose indicative of a colder environment. It is of considerable interest that all five species characteristic of Peypouquet’s V2 thanatocoenose I, namely Robert- sonites tuberculata (Sars), Finmarchinella finmarchica (Sars), Eucytheridea punctillata (Brady), E. bradii (Norman) [as E. bairdii (Sars)], and Acantho- cythereis dunelmensis (Norman), are well represented in the Russian Harbour fauna. Eucytheridea punctillata shows a similar distribution to Robertsonites tuberculata. In the past Eucytheridea macrolaminata (Elofson) has been con- fused with E. bradii. Elofson (1939) found it from King Charles Land, between Bear Island and Hope Island, from Clavering Island and Cape Steward. Van den Bold (1961) described material from Russian Harbour and Hazel (1970) has found it off North Wolstenholme Island in West Greenland and off Clavering Island and Cape Stosch in East Greenland. The present authors have found it in Colonel Feilden’s material from Matochkin Shar, Novaya Zemlya. Its known distribution is exclusively Arctic and is shown in Text-figure J. W. Neaze ano H. V. Howe 00-OoL to} oO io n ° fe} Oo NS 96:29 sajjuaanr 42 25D % SvINPYV 00:sz () 99°\y Sl: eL booby zZ:SE SE‘zE 61:°SE Qr're €e€:' ce 69:82 z9° Op g9°ce ze'ly ze-ee £€°0€ pele Lhe €c SE 61 tL 61 OL Sv ev fo) 40:0 L L (e) {e) L 10) te) (e) 20-0 t t fe) ° L fe) fe) (0) 20:0 L O 40:0 ‘ L 20:0 t ie) are} € le} ecO0 v L tc-O € Le} evo 9 Ss vL:O @ S gc-0 v 6 40:0 t 6 4 Ae) 9 @ pS 22 v4) €9'0 6 SL 02:0 OL €z 6:0 z OL Ort od eL 16-0 el SZ 16:0 €L Le ¢3:0 et Le 24:0 LL <4 684 Ze ge e6:0 tL a2 Ll Ge lek LE-2@ ve Ss 95:0 8 se sod ge 62 JAP ANS vs ze LLE vS £6 cov? 62 €6 LOVE vr PLL BOL ve OL 12-6 cel BZ Slv 89 [A] Lviv v9 Stl €9'9 S6 LOE BOL OlL oe2 9S-e2 ost 6re cll Sv Svs Sse-6 vel oe sajjuaanr punb4 SiInpYy ‘ON FINPY "ON £0:0 L £0:0 L €0:0 L £€0:0 t £0:0 L £0:0 L €0:0 L £0:0 L so:0 @ 80:0 £ [eo] ie} v fo} Fe) v Sto 9 BLO Zz €2:0 6 scz:0 OL Z€:0 SL 09°0 ve s9:0 92 s9:0 92 SZ0 oe sZo Of £240 Le S60 se 46:0 6€ Oct er Lob LS OEt 2s eet €s sel vS Sol cg O61 92 40:2 £8 gece 16 Sle Sel ere ZEL Sve Sel Z£Ge Epl SOE OPL SOE OPFl 20:9 lee 220! Lip 6r ll O9r pect vér e6'9t oss °lo puno4y 1D}OL ‘ON zZAou ‘ds DynyaysA2/ was ‘ds é DunseysAIDIJ a ‘ds i avayjAD0U0SUag (Apd4g) Duayijngo)6 piuojspunoy SUDS DII]O0dg J2 SludAIDIDY (Apd4ug) DJDNIID'g 42 SioyvaysAIDIDY (S4DS) Daujing ‘WD siouvay{AIDID_ Apdsg awyosiSua DWO}SOXOPDIDY SIDS WN//AYIINdY 410 DWoOJSOxXOpDuDY (Asyssou5 9 Apdug) MausayooDW DYdsowoaYysAQ L’aou ‘ds DuNveYysADIWaS (S4DS) SijiwiS DuNyaYyJAIIWAS (uoszueqoy Aayssoud ‘Apdug) Dyaua} sioyaysAIDIDA (Apdug) siDUOlujUa}das Siw}iqDYy SIDS DJOIujSuOD ayaysAIOYAG aou ‘ds uovaidovaysAQ ‘ou ‘ds siouay}AQ Ss4DS Daplouo0d DIDa0))//buy @MOH 3 9ID8N WNID)DOSOpoU 9°}? UOUaIdoyaY}IAD (UDWION) NW PDIG DaplvaysAINZ (sau0r) DUDAQUOS SlapljdAI0Ja} aH uosjo|3 DI/}J2UD DWO}JSOXxOpDUDY (UDWJON) SNJYO}JUOD sNjiyIova}IS (UDWIJON) D/OD/WI) D)}aUaW)Dd (S4DS) DO/YIVDWUIJ D}jau/YosDWUIy (S40S) DJD/NBuD DjjaulyouDWUIy (S4D0S) DJDUYIDID DINveYy)ADZIWAaH SIDSN DysodAUND D))au/YIuDWUIy ®MOH BY 9IDAN WNI}IVD UOVa}dovaYy}AZ (S4DS) S/ulJJD DuNvaYyj{ADIWeaS J3IINW 4'O Dan) asayjAQ S4DS DSSaudap sisaqgea/Ojsax (UOS}JaqoYy ‘AayxssoOjD ‘ApD4G) DUJUGDUOD DUNVEY}ADIWAaS Aposg ajppiwosAd udusajdovayjAQ (UDWION) S/ISUAW/AUNP SlayvaYyiADOYJUDIY @MOH 8 AID8N WNID/DOSOPOU UOdUa}douaYy}AQ (UDWJON) DW yapo/a) AavaY}ADIUDWION (S4DS) DJDPUN Dunsey}AdIwas UIDMS WNWISSI}D)DUDA UOUadOVaYyAQ (WD S|PPUDW) S/SUBOAOZJUAIDG Djjau/yIsDWUIy (UOSjO}/3) DJDUIWD/OVIDW DapilvayjJAINZ (Apoug) DIDINIUNd DaplvayJAINZ (s40S) DJDU/ByDWea aay ADIUIJJDg 19Z0H J/amMOY aveYyjAIIUIZJOg (S4DS) DJD)/NIVaGnN} SejJiuOSs}yaqoy DA|WAZ DADAON ‘NOGIDH UDISSNY WoO Us DP!coD0pog auluDW ‘| B/QDL Two vwqT a oO Ne ovrvVywy oO om KF AMTNORMHMODAMYTNHNORMMOTAMYNORMOOTAMNTMHOON eT rere re ehe Ke HANAN N ANNAN ANAM OMOMOMOMMOM Hicu LaTITuDE MarRINE OsTRACODA 389 3. The hemicytherinid species Baffinicythere emarginata and B. howei are both characteristic Arctic forms although not confined to that region. B. emarginata is fairly widely distributed as far south as northern Britain in the eastern Atlantic and as far South as 41°N in the western Atlantic. It is most abundant in Arctic seas at depths of less than 25 fathoms and becomes rare and sporadic towards its southern limits, a feature clearly appreciated by Brady and Norman (1889). B. howei is similarly distributed but not so well known on the eastern side of the Atlantic. It, too, is confined to the Norwegian and Arctic Provinces not venturing south of the Shetland-Faroes ridge, a fact which may be linked with a change of the order of 6° to 8°C in bottom temperatures across the ridge. The next six species in order of abundance contain some typically Arctic forms. Finmarchinella barentzovoensis (Text-fig. 2) was first described from Russian Harbour by Mandelstam (1957) and has since been found at a number of other localities in the Arctic in both the H.M.S. Vidal and Ernest Holt material and in Museum material from the Hunde Islands and Holsteinsborg Harbour in West Greenland. It has not so far been found below 66°N in the Eastern Atlantic although it is found in Frobisher Bay and Kneeland Bay in the Western Atlantic at 63°10’N, 67°45’W and 62°59’N, 67°28’W respective- ly and also appears to be present in the Gulf of Maine at 44°08’N, 68°13’/W. Cytheropteron paralatissimum originally described by Swain (1963) from the Pleistocene Gubik Formation in Alaska has been found in the Hunde Islands, Greenland and Franz Joseph Land material (where it was placed in C. latissimum), and at Novaya Zemlya and has so far not been found outside the Arctic. Semicytherura undata (Sars), eighth in order of abundance between Cytheropteron paralatissimum and Normanicythere leioderma, has a distribution reminiscent of Robertsonites tuberculata, and the same is true of Acantho- cythereis dunelmensis (Norman) which is eleventh in order of abundance. Normanicythere leioderma (Norman) a characteristic Arctic species which is also found in the Norwegian Province has been described and its distribu- tion and affinities covered in a series of papers (Neale, 1959, 1961, Neale and Schmidt, 1967) and needs no further discussion here. The allied N. concinella Swain does not occur at Russian Harbour although it occurs fossil in the Pleistocene of mainland Russia (v. Lev, 1969). Cytheropteron nodosoalatum Neale and Howe has so far only been found in the Arctic eastern Atlantic. The less abundant species show a similar general division into two types- characteristic Arctic species such as Rabilimis septentrionalis (Brady) Fin- marchinella curvicosta Neale, Cytheropteron arcticum Neale and Howe and C. cf. C. nodosoalatum Neale and Howe, and those which have a more ubiqui- tous distribution such as Cythere lutea O. F. Miller, Finmarchinella fin- marchica (Sars), Heterocyprideis sorbyana (Jones), Semicytherura concen- trica (Brady, Crosskey and Robertson), and others. In summary one can say that the fauna is characterized, firstly by a number of typical Arctic species, secondly by a number of species whose range is wide but which are much more abundant in Arctic waters, and thirdly a 390 J. W. NEALE anp H. V. HowE @ Eucytheridea macrolaminata (Elofson) a GS : a LY AN a vA > .. i: - oN ye \ a =U 2 Dy, Vaz y ° . ze) "0 - fs of $0 iA ——— 20C METRES .. 3000 METRES Text-figure 3. Distribution of Eucytheridea macrolaminata (Elofson). group of wide ranging species which show no change in abundance or an abundance which increases southwards, this third category forming a minor element in the fauna. Here we may remark on the absence of typical Loxo- conchidae and Leptocytheridae so characteristic of shelf areas farther south. These are represented in the Barents Sea and other Arctic Seas by rare examples of the two small, tuberculate genera Roundstonia (loxeconchid) and Cluthia (leptocytherid) which are fully adult at only about two-thirds the length of typical members of these families and show marked sexual dimorphism. It is uncertain whether Roundstonia globulifera (Brady), which is represented by a single valve at Russian Harbour, is still living. Cluthia cluthae (Brady, Crosskey, and Robertson) is found at Matochkin Shar and is regarded as a living species. As well as plotting the total population, the adults were plotted separately in the same manner to gauge the effect of juveniles on the abundances. This had two main effects. Firstly, it modified the order of abundance in the case of some of the larger forms, particularly noticeable in the case of Robertsonites tuberculata which had a large number of juveniles present at the time the sample was taken. Secondly it increased the relative proportions of the smaller species such as Semicytherura undata (Sars), S. concentrica (Brady, Crosskey and Robertson), Xestoleberis depressa Sars, and others. Hicu LatirupE Marine OsTRACODA 391 The same exercise was carried out for two other samples. In the case of Ernest Holt Station 6 (Text-fig. 9) the differences between the total popula- tion and adult only plots were slight. In H.M.S. Vidal Station 6 the results were somewhat intermediate between the other two. The results reflect two main factors. Firstly, the size of sieve used which controls the minimum size retained and thus means that specimens which only attain a small adult size are under-represented in the total population, although, it must be added, that provided each sample is accorded the same treatment the samples are strictly comparable. Secondly the number of juveniles in any one species is a re- flection of the particular breeding season together with a random factor in the sample itself and this may well explain any apparent discrepancies between the two sets of data. Provided enough specimens are available it is preferable to consider only adults, always providing that a check is made on juveniles to ascertain that sorting and transport is not affecting a particular fauna. On the other hand, with total populations, if all samples are treated in the same man- ner, they will be comparable between themselves although perhaps not such a true reflection of the actual faunal composition. In this latter respect one must also bear in mind that the fragile, thin-shelled forms may be under-represented. In the Novaya Zemlya, Ernest Holt 6 and H.M.S. Vidal 6 faunas the adults represented respectively 35.96%, 35.22%, and 30.21% of the total pepulation which shows remarkable agreement from three widely scattered areas. These populations are considered to be indigenous breeding populations and there is nothing to suggest sorting. Only in the relatively rare cases of single specimens of rather small size may derivation be suspected. This is possibly the case with the single valve of Roundstonia globulifera at Russian Harbour mentioned above and in the case of one or two other specimens. Another aspect which was noted was the proportion of males to females in those species where the sex was determinable, and the data are given in Table 1. The results were much as expected. Finmarchinella angulata (Sars) with 18.18% males showed the lowest ratio. The other 15 species all showed proportions lying between 25% (Semicytherura, sp. nov. 1) and 44.44% (Hemicytherura clathrata) with a clustering round about the 32-35% level for the majority. In most cases a good working rule would seem to be about one-third males and two-thirds females and as far as it is possible to tell there is no tendency to increasing parthenogenesis among these marine forms in colder waters. Some comparisons with other faunas can now be made. COMPARISONS WITH OTHER AREAS 1. Novaya Zemlya, Matochkin Shar One of the most interesting discoveries made during the course of the present work was two slides brought to light during work on the Brady Col- lection in the Hancock Museum, Newcastle-upon-Tyne. These were labelled respectively “Sounding 10 fathoms Matyushin Shar June 24. Capt. Feilden” 392 J. W. Neate anv H. V. Howe and “Sounding 15 fathoms N. side Matyushin Shar (Capt. Feilden)”. These are obviously from what is referred to on current maps as the Strait Matochkin Shar which provides a sea passage from west to east through the middle of the island, the settlement of that name lying at the eastern end. As far as the authors know these slides have never been described or mentioned in the literature. Research has revealed a little about the circumstances surrounding their collection. In 1897, following an unsuccessful attempt two years pre- viously to penetrate ice in this area, Mr. H. J. Pearson with three com- panions (one of whom was Colonel Feilden who acted as naturalist), chartered the Norwegian steam yacht ‘Laura’ which sailed from Bergen on June 4th, arriving back at Trémso on August 20th. An illuminating and entertaining ac- count of this voyage is given by Feilden (1898). The expedition sailed right through the Strait into the Kara Sea and northwards for some distance along the eastern side of northern Novaya Zemlya. Unfortunately the position of the dredgings is not given. Statements that “At mid-day Nameless bay opened up; we stopped and sounded 3 miles from shore, and got 20 fathoms” (Nameless Bay is about 20 miles south of the western entrance of the Strait) and that on the way back “Before quitting the strait, the ship was stopped for a few hours, and Mr. Pearson ascended a mountain” suggest that the soundings may have been taken on the western side, and this is indicated on figure 2. There is no reason, however, why the soundings might not equally well be from the Strait itself or from the eastern side and this should be kept in mind. The date ‘June 24th’ which appears on one slide is quite unhelpful and is unconnected with the collection of the sample. As might be expected, both soundings show a closer relationship to the Russian Harbour fauna than to any other fauna. A. The ten fathom sounding yielded altogether 17 specimens belonging to seven species: 3 Acanthocythereis dunelmensis (Norman) 1 male carapace, 1 juvenile left and right valve 1 Rabilimis septentrionalis (Brady) 1 juvenile carapace 3 Eucytheridca macrolaminata (Elofson) 2 carapaces & 1 juvenile left valve 2 Eucytheridea bradij (Norman) 2 carapaces 2 Eucytheridea punctillata (Brady) 1 female and 1 male carapace 5 Palmenella limicola (Norman) 3 carapaces, 1 right and 1 left valve 1 Cluthia cluthae (Brady, Crosskey, 1 carapace and Robertson) The P. limicola correspond with the subspecies denticulata described by Akatova (1946) from the Novosiberian Shelf with the small spine terminating the principal ventral rib postero-ventrally. All these species except for Cluthia cluthae represented by one small carapace (1. = 0.338 mm) occur in the Rus- sian Harbour fauna. Hicu LatirupE MARINE OsTRACODA 393 B. The 15 fathom sounding consisted of seven specimens belonging to four species: 1 Eucytheridea macrolaminata (Elofson) 1 carapace 2 Eucytheridea punctillata (Brady) 1 carapace, 1 juvenile carapace 2 Robertsonites tuberculata (Sars) 1 juvenile left and 1 juvenile right valve 2 Argilloecia conoidea Sars 2 left valves (\) 4 ea Ginevra Bay y ay \ e : Ms 7 % wp L a *e i oe = 4 Po we, / Aavatsmarkbreen oe iy, 8 & Schatdinn li Speen gieleem eas ‘ te Station 6. 1898 | oN ‘ a - . £ > = ‘i: = = > — Pa % Te = — > FA ay € v.468 ae Ne: = | eet uf 2 | V.390 OV.38 = & yt tose oi } | A 4d | 3 | | fe) E=Wtochkin Shar, oe. gm auZ v.48 f pe > ai | fats | | } } Ay iad ova da eli i peenesy iigaay [ec uhisls sic eeaii ae | ; &\ 5 f ) & SS “wy te | ay 8 at } Px —s Fe an = e . a a - | S i ne | hates i ¢ l ¢ R. Pachoral si Hi, a : oy il = Z “ah: |) set R. Yenesei a4 a Se ee 3 2s oa Seg 7 a el ji a RSE pis ad s : ape oP eT = a is ¢ | v 2 ] 3 Voda 2 Sag a Jans ~ IR. Mezen re DES { ; S) A, 1! ? gf 3 Text-figure 4. Location of sample stations and some places mentioned in the text. All these species occur at Russian Harbour. The juvenile carapace (1 = 0.305 mm) almost certainly belongs to EF. punctillata but at this size a certain amount of doubt must attach to the identification. The Nordenskjold Expedition also collected material at Matochkin Shar and Elofson (1941) recorded two marine podocopids Heterocyprideis sorbyana (Jones) and Eucytheridea bradii (Norman) [as Cytheridea papillosa Bosquet] both of which occur at Russian Harbour. 394 J. W. Neate anp H. V. Howe 2. The Novosiberian Shelf Akatova (1946) described a limited fauna of ostracodes from a number of stations on the Novosiberian Shelf. It is difficult to assess the relationship of the fauna to that of Russian Harbour. Paracyprideis fennica Hirschmann and Eucythere undulata Klie which are found in the northern parts of the Laptev Sea do not occur at Russian Harbour nor does Krithe glacialis (Brady, Cross- key, and Robertson). Rabilimis mirabilis does not occur at Russian Harbour but at least some of this material is in fact R. septentrionalis (Text-fig. 2 and Akatova 1957 p. 432 where it is recorded from a depth of 19 m — presumably indicating Station 81 at 75°37’N, 131°36’E). Palmenella limicola occurs in both areas as does Bythocythere constricta Sars which she records as B. mon- trosiensis. In B. constricta (Pl. 4, fig. 4), the surface ornamentation is very well developed in these northern communities. The form which she figured as Hemicythere angulata G. O. Sars, is in fact Finmarchinella barentzovoensis (Mandelstam) the type area for which is Russian Harbour, and Eucytheridea bradii also occurs in both areas. Unfortunately Akatova did not deal with the Cytheropteron species which she found, because of “the intricate characteristics of this genus’ and so no comparison of these is possible. There are obvious similarities between the two areas, the characteristically cold water R. septen- trionalis (Text-fig. 2) being a case in point. Until more detailed work is done on the Novosiberian Shelf it is not possible to say whether there is in fact an “Gce cellar” effect (Feilden, 1898) in the Laptev and Kara Seas which is discernible in the faunas, unless the presence of K. glacialis in the area and not on the western side of Novaya Zemlya can be taken as significant in re- flecting the warming influence of the Gulf Stream. In the Kara Sea there are also isolated records of Eucytheridea punctillata at 73°38’N, 63°45’E in 77 fathoms and Heterocyprideis sorbyana at 71°6’N ca. 63°E in 16 fathoms collected by the Vega Expedition (Elofson 1941). 3. Franz Joseph Land One of the nearest areas to Russian Harbour where comparative sub- littoral faunas might be expected is Franz Joseph Land. Scott (1899) described the fauna brought back by the Jackson-Harmsworth Expedition of 1896-7 and through the kindness of Dr. A. Rodger Waterston it has been possible to bor- row the material from the Royal Scottish Museum, Edinburgh for re-examina- tion. The 13 slides of marine Ostracoda confirm most of Scott’s findings but some of his records need modification. They confirm the presence of Pontocypris (2?) hyperborea Scott, Sclerochilus contortus (Norman), Pseudocythere caudata Sars, Xestoleberis depressa Sars, Eucythere declivis (Norman), Semicytherura undata (Sars), Hemicytherura clathrata (Sars), Cytheropteron angulatum Brady, Heterocyprideis sorbyana (Jones), Palmenella limicola (Norman), Cluthia cluthae (Brady, Crosskey, and Robertson), Acanthocythereis dunelmensis (Norman), Baffinicythere emargi- nata (Sars), B. howei Hazel, Rabilimis septentrionalis (Brady), Robertsonites tuberculata (Sars), and Polycope orbicularis Sars. Hicu LatirupE Marine OsTRACODA 395 The excellently preserved paradoxostomatids prove to be Elofson’s species Paradoxostoma arcticum, not P. variabile (Baird) as thought by Scott. The two specimens from 30 fathoms off East Glacier are not Roundstonia globuli- fera (Brady) but the young of Robertsonites tuberculata (Sars), and the former can be removed from the species list. The same is true of Rabilimis mirabilis (Brady). The authors were fortunate in having Brady’s material of R. septentrionalis (Brady) from the Hunde Islands, Greenland, in front of them when examining this fauna and the three specimens Scott regarded as R. mirabilis are in fact pre-adult forms of R. septentrionalis. Much of Scott’s R. septentrionalis material is excellent but under this heading he has included a large number of specimens of another form. The Franz Joseph Land Fauna only became available at a late stage in this work and this form, which is represented by well-preserved closed carapaces, is still awaiting detailed examination. On general shape and ornamentation it has been placed in Cytheretta and this will form the subject of a separate study at a later date. The cytheropterons required some revision. The four specimens from 15 fathoms off Cape Flora labelled C. pyramidale Brady are C. paralatissimum Swain although the true C. pyramidale does occur as a single specimen from 30 fathoms off Cape Gertrude. The three specimens from 2 to 4 fathoms off Cape Flora placed as C. latissimum (Norman) consist of one specimen of C. nodosoalatum Neale and Howe, and two of C. punctatum Brady. The two specimens labelled C. pyramidale and C. pyramidale ? in slide No. 2 from the same locality also appear to belong in C. punctatum. The largest group of Cytheropterinae agrees better with C. inflatum sensu Sars than with C. sub- circinatum Sars. The material agrees very well with Sars figure but differs from actual material we have in front of us from Dryleys, Montrose which Brady, Crosskey, and Robertson placed in this species. Brady, Crosskey and Robertson (1874) are regarded as the arbiters of this species, because although figured by Brady six years earlier in the Annals and Magazine of Natural History the species was first described by the authors of the former work. There has been insufficient time to make a detailed analysis of the material placed in Semicytherura by Scott but it seems that at least three species are included in material assigned to S. fulva (Brady and Robertson). Part of the material agrees with the single specimen from Novaya Zemlya tentatively assigned to Tetracytherura sp. and is so shown here. Part of the material belongs to S. similis (Sars) which can be added to the species list and the other species has for the present been left as Semicytherura sp. The Paracy- therois is for the time being placed as P. cf. flexuosa (Brady). The ‘Cythere marginata Norman’ of Scott’s paper, taken in 15 fathoms off Cape Flora appears to be recorded on the two slides from this locality as ‘Cythere laticarina’. In neither case do the specimens belong to these species. The four specimens in Slide No. 1 belong to Finmarchinella finmarchica (Sars) which may now be added to the species list, and the one specimen in Slide No. 2 belongs to Baffinicythere emarginata (Sars). Thus out of the 30 species of marine Podocopida from Franz Joseph Land, 19 or 63.3% are also found 396 J. W. Neate anv H. V. Howe in the Russian Harbour fauna, which emphasizes the great similarity between the two faunas. Scott’s slides cover the Cape Gertrude and East Glacier localities and three stations between 2 and 5 fathoms off Cape Flora, with an additional five slides of duplicate material labelled ‘Vicinity of Cape Flora’. The latter, together with the three Cape Flora stations have been combined to give the composite data plotted on Text-figure 9. Details of the individual faunas are given in Table 2. The only addition to Scott’s list given by Miller (1931) is Cytheridea dentata Sars, now regarded as a synonym of Heterocyprideis sorbyana (Jones). 4. Spitzbergen Details of ostracode faunas from Spitzbergen are very limited. A paper by Klie (1942) dealing with the material collected by Romer and Schaudinn in 1898 gives some of the best information on Spitzbergen and his updated taxonomy is given below. In his Fauna Arctica (1931) Muller augments the Spitzbergen fauna considerably adding Bythocythere constricta Sars, Bythocythere turgida Sars, Paradoxostoma variable Baird, (probably = P. arcticum Elofson), Xestoleberis depressa Sars, Semicytherura rudis (Brady), Cytheropteron hamatum Sars, Cytheropteron latissimum (Norman) (probably = either C. paralatissimum Swain or C. dimlingtonensis Neale and Howe), Eucytheridea bradii (Norman), E. punctillata (Brady), Acanthocythereis dunelmensis (Noiman), Elofsonella concinna (Jones), Muellerina abyssicola (Sars), Pterygocythercis jonesti (Baird), Robertsonites tuberculata (Sars), and Cluthia cluthae (Brady, Cross- Station 6. Stor Fjord at the entrance to Ginevra Bay, 105-110 m, blue, sticky with some smal] stones set in loam. Station 15. S. entry to Hinlop Strait at Behm Island, 80 m a little mud with stones up to fist size. Station 20. Advent-Bucht in Eis Fjord, 40 m, blue mud with small stones. Station 24. Ca. 12 sea miles W. of South Cape, 135 m, fine blue mud mixed with sand in many sizes part-rolled, part sharp-edged stones. Station 25. S.E. coast of Edge Land, 20 nautical miles N.E. of Halbmond Island, grey-blue mud with mollusc shells and worm casts and many, head sized, part-rolled, part-slaty stones. Station 31. In front of a large glacier on N.E. Cape of Konig Karl’s Land called Jena Island, 36 m, Coarse-grained blue mud with a few small stones. Station 41. Ice sea N. of Spitzbergen 81°20’N, 20°30’E at land ice edge, 1000 m blue mud with a few small to nut-sized stones. Table Land 2 Details of the Franz Joseph Cape Flora 79° 57'N 50° O1'E Land Ostracod Faunas. a. ae ete ire se iets Flora Composite Off Cape Off East One Mile 2-10 fms Cape pisea Si va Spee Cero Gertrude Glacier . uplicate 2-15 fms. 30 fathoms Cape Flora 15 fathoms 2-4 fms. Ostracoda No "Io No le } Heterocyprideis sorbyana (Jones) 7 18 2s 7-79 2 Robertsonites tuberculata (Sars) 5 9 14 4.36 1 5 7.14 3 Eucytheridea bradii (Norman) 5 4 20 29 9.03 4 4 5.71 4 Eucytheridea punctiliata (Brady) 5 10 15 4.67 1 5 Finmarchinella finmarchica (Sars) 4 4 1.25 6 Cytheropteron paralatissimum (Swain) < 4 1.25 7 Baffinicythere emarginata (Sars) 3 1 6 28 38 11-84 : 6 8.57 8 Cytheretta sp. 3 4 16 23 7-17 9 Acanthocythereis dunelmensis (Norman) 2 2 0-62 10 Rabilimis septentrionalis (Brady) 2 2 4 1-25 z. 10-00 i Polycope orbicularis Sars 2 7 9 2-80 1 172 Sclerochilus contortus (Norman) 1 2 12 15 4-67 3 193 Xestoleberis depressa Sars 1 1 1 4 7 2-18 3 4-29 14 Pararadoxostom arcticum Elofson 1 7 21 29 9.03 % Semicytherura sp. 1 2 5 8 2-49 5 7-14 ’ % Pontocypris(?) hyperborea Scott 1 1 0-31 7 Cytheropteron punctata Brady 3 3 0-93 4 5-71 1% Cytheropteron nodosoalatum Neale & Howe 1 1 0.31 19 Cytheropteron inflatum sensu Sars 1 39 40 12-46 1 20 Semicytherura undata (Sars) ’ tT Siem 5 =e | 21 Paracytherois ct. P flexuosa (Brady) 8 8 2-49 22 Tetracytherura sp. ? 6 6 1:86 7 10-00 _% Pseudocythere caudata Sars 4 4 ie 24 Hemicytherura clathrata (Sars) * % 1a > rie ce Semicytherura similis (Sars) 4 4 1-25 § Cytheropteron angulatum Brady & Robertson 3 3 ees 3 4-29 ‘opteron pyramidale Brady ‘ — ella limicola (Norman) ‘ eynuimsied essiayyAg sisdopuddéy siudAoejay (a)suudAsojads3 gJdA0A}| s1dAo0|9A9) euopued ZHQbGeeGOew 8 ea a Boq 3J3ASONVI 33SNI37y auoys jsea aaS Y3aNIZdO1x 438 H. LorFier In order to learn about the onset of meromixis in Klopeiner See a core well below the lowest level of the mixoiimnion at 33 m was taken (maximum depth 46 m). Ostracodes in the lowest part obtained (Cytherissa lacustris and Candona candida) occur between Bdlling and Preboreal according to pollen analysis and then cease abruptly, although the sediment then differs but little from that of the holomictic Lunzer Untersee. Along with the ostracodes, head capsules of chironomids also decrease dramatically and only very few individ- uals can be found throughout the core even in the most modern strata. These, as with the few ostracodes from the littoral, most likely spread to the profundal by drifting. It should be mentioned that the sedimentation rate in Klopeiner See it extremely low (from Alleréd until now ca 3.5 m, compared with Lunzer Untersee: about 8 m!) because of the lack of any important inflow (fed mainly by submerged springs). Therefore, the exact identification of the time of onset of ostracode disappearance is somewhat vague but is certainly not earlier than Alleréd and not later than Preboreal. Mica is abundant in the sediment only until 345 cm which corresponds, as in the core from the eastern shore, to I C. Particles of mica can be, however, found at 340 cm though they are rare and may have drifted from the littoral when, during the initial period of the existence of the modern lake, mica-containing sediment still was exposed to wave action. As mentioned, Klopeiner See in contrast to its shallow and holomictic twin Kleinsee has been meromictic at least since the first observations in 1931 and because of climatic features of the area. Findenegg (see 1965) has verified its meromictic conditions several times in detail. The onset of meromixis in this lake, however, was not known. From the profundal core it seems most likely that at least a severe decrease in oxygen if not meromictic conditions did occur at the time of the disappearance of the profundal fauna both of ostracodes and chironomids. This then would have happened during the first holocenic warming most likely during Preboreal and according to the available information well after the collapse of Kthnsdorf See. The explanation for the beginning of meromixis could be the changeover of the lake from a cold polymictic stage in the late Pleistocene into a dimictic one during the holocenic warming which does not, according to Findenegg, provide for regular full circulations in this area and in deeper lakes lacking any big inflow. To verify this hypothesis investigations of many more of the meromictic lakes in the same area are, of course, necessary. Thus far only Lingsee has been studied in this respect. The results obtained not only strongly support the interpretation of the beginning of meromixis outlined above but are also of interest since a detailed paleolimnological study of this lake had been carried out previously (Frey, 1955). Langsee another small and shallow lake (maximum depth 22 m) in southern Carinthia belonged to the same Drau glacier system as Klopeiner and Kleinsee. Its elevation is approximately two hundred meters above that of the latter. The most obvious feature in contrast to the Klopeiner See core is the extent of sapropel in the uppermost section. Below and after a transition zone almost purely organic and brownish material starts which may be compared OstTracopEs ALPINE AND PREALPINE LAKES 439 with the situation in Klopeiner See where from three meters downward this brownish organic material is replaced by finally almost purely inorganic gyttja containing mica. As Frey (1955) has carefully described, the lower onset of the sapropelic transition zone (with alternating brown and black layers) is also marked by the appearance of pollen of various agri- cultural weeds indicating the presence of man several hundred years B.C. Frey then identifies the sapropelic part of the core with the time Langsee has been meromictic (about 2000 years) and he thinks that early agricultural activities resulting in the clearing of the forest around the lake finally led to increasing runoff of morainic clay into the lake and a triptogenic factor initiated biogenic meromixis. As indicated above the author was at that time using counting samples of 0.1 cc which is normally adequate for the study of groups such as chydorids or protozoans. Frey thus was able to give a very careful account of the chydorids which, however, mainly reflect littoral condi- tions and hardly any profundal events. On the other hand his samples were obviously too small for the detection of any ostracodes apart from a single shell of Candona (at a core depth little less than 4 m) which at the same time was the first organism he found in his core. Text-figure 2 presents the ostracode development found in the present core and close to the area of maximum depth. It starts with a Cytherissa maximum in late Pleistocene which on current evidence probably indicates a warmer period before Bolling. A second period of ostracodes (Bdélling) which ceases probably during I C is composed of Cytherissa lacustris and Ilyocypris cf. lacustris. During the last ostracode period (Alleréd?) which in its general shape resembles that of the profundal core of Klopeiner See, though there it is much more compressed, Ilyocypris being present only at the beginning followed by Candona candida. Cytherissa lacustris is present throughout the entire period which in contrast to Klopeiner See (where it has at present a very restricted area of distribution in a littoral section) in modern Liangsee is lacking. This third ostracode period ends (as abruptly as its starts) approximately during Preboreal and there are no ostracodes found in the rest of the core apart from a few shells of the littoral Cyclocypris. Again, as in Klopeiner See, chironomid head capsules decrease together with ostracodes and drop from about 100/5 cc at 340 cm to virtually none above three meters, although an isolated individual may be present in a sample of the size mentioned which, however, is also true for the sapropelic section. As Frey has also observed Chaoborus starts to become abundant above 280 cm and thus well below the sapropelic part of the core. (Chaoborus has not until now been detected in the Klopeiner See core though a small popu- lation of it lives in the lake at present.) Chaoborus is not necessarily indicative of hypolimnic water lacking oxygen though in the Carinthian meromictic lakes it is one of the common organisms. Langsee, thus according to the evidence afforded by the ostracodes, almost certainly became meromictic in early Holocene and a more detailed study of chironomids would probably verify this statement. It is therefore only the onset of the sapropelic section which may be related with the early agricultural 440 H. LorF_er activities in the area. Such a sapropelisation (excepting a few black layers within the top centimeters) never occurred in Klopeiner See and preliminary heavy weight coring in Worthersee further indicate its absence though parts of this lake have become sapropelic through sewage. Thus Langsee and Klopeiner See have about the same time of onset of meromixis. In Liangsee, however, climatic factors may have played only partly a role in the onset of meromixis insofar as the early lake’s extent was considerably greater and subsequently became reduced during the late holo- mictic stage. The lake at that time not only lost its southern portion which gradually altered into the present-day bog but according to preliminary investi- gations must also have, at some time, incurred a lowering of water level to the extent of at least one meter. The time of that event, however, is not yet known. Therefore, in Langsee both the climatic charge in the early Holocene as well as a decrease in lake area may have resulted in meromixis. Text-fig. 2 also presents the development of the ostracode fauna in the southern basin of the early lake. The core was taken about 600 m south of the actual shore and collected from 10 m upward through boring even down to 17 m did not reach morainic gravel. Three periods of ostracodes may once more be distinguished. The first, below 7 m, consists of Candona candida, Ilyocypris lacustris, and Cyclocypris cf. ovum (Jurine, 1820). Strangely enough Cytherissa was not pres- ent at this time. There is some evidence that this period is not identical in time with the first one described from the profundal core. The second one, how- ever, may correspond to it. Situated between 6 and 7 meters it shows a distinct succession of Cytherissa lacustris and Ilyocypris cf. lacustris followed firstly by a Cyclocypris and then by a Candona candida maximum. During the late stage of this period Erpetocypris is also present. The third period starts only 20 cm higher and consists almost exclusively of Candona candida followed initially by Candona rostrata which finally totally replaces the former. The other species occurring during this final period before bog formation are mainly Cyclocypris cf. ovum and Darwinula stevensoni Brady and Robertson, 1870, and to a lesser extent Erpetocypris sp., Cypria ophthalmica, Cypridopsis vidua and Limnocythere inopinata Baird, 1843. Most likely this last period of ostracodes corresponds to the late Pleistocene (Bolling onward?) and early Holocene whilst it vanishes during the Preboreal. SUMMARY If one summarizes the data so far obtained for the evolution of ostracode faunas in alpine and prealpine lakes it appears that in the profundal of medi- um- to large-sized lakes Cytherissa lacustris is the first species to occur in late Pleistocene followed by the few other forms which still belong to the profundal fauna. In the sublittoral and perhaps also deeper Ilyocypris cf. lacustris and Candona candida may be among these pioneer species. In all of the lakes observed a striking change in species or their abundance occurred during the early Holocene. In addition to changes in thermal and nutrient conditions the onset of more organic sedimentation must have played a fundamental role. OstTRAcoDES ALPINE AND PREALPINE LAKES 441 Even before the onset of the Holocene remarkable periods of ostracodes may be observed in Lingsee and most probably reflect warmer periods such as Alleréd, Bolling. All of the lakes belonging to the Drau glacier system are lacking in Limnocythere sanctipatricii, a species otherwise most typical of alpine lakes and cold water both littoral and profundal. All the lakes mentioned so far are subjected to a more or less normal seston and fluviatile (especially Lunzer Untersee) sedimentation. In the shal- low (maximum depth at present 2 m) and large (at present some 300 km?) art eae Een pe ? oa 7,5 km dy " Sars - @ C.lacustris SENS Vy, 4 : 8 L.inopinata ie Sep US ) ry L.sanctipetricii C PIN aie aaa (+) W.cordata i ——_——_ imit of gravel: Text-fig. 3. — Localities of subfossil Cytherissa lacustris, Limnocythere 3 sanctipatricii, Limnocythere inopinata, and Metacypris cordata east and west of Neusiedlersee (its configuration presented together with the extent of the Phragmites belt). Numbers indicate the drilling profiles carried out by OMV in 1971. Dotted area: extent of Pleistocene gravel. Broken lines: Depth of rock. From Léffler (1972). 442 H. LorF_er Neusiedlersee most recent sediment (Léffler, 1971) is deposited on top of Tertiary (Pannonian) material and is thus lacking in any older Holocenic or even Pleistocenic deposits. This is due partly to the fact that irregular periods of drought and flooding are experienced as well as a shifting of the sediments from this shallow lake into reed belts resulting in a frequent renewal of the sediments present at any time. It also reflects the origin of the lake which represents a subsidence of late Pleistocene (and early Holocene) origin. Ostra- codes in this case have been used not only to describe the extent of the former lake but also to learn from their associations something of the climatic condi- tions present at various stages. More than a thousand drill samples (mainly taken by an oil firm) have, therefore, been collected around the lake as has been described elsewhere in greater detail. Text-figure 3 illustrates only those localities where species of interest have so far been found (mainly Cytherissa lacustris, an indicatory species for non-periodic bodies of water, Limnocythere sanctipatricii, an indicatory species for cold water and Limnocythere inopinata which is most typical of the present lake (besides Ilyocypris gibba and several species of Candona in the reed belt) and which tolerates wide ranges of salin- ity and thermal conditions though it never occurs in permanent cold water lakes). From this distribution it appears that a precurser of the present lake existed during a cold period, the maximum temperature of which was unlikely to have exceeded 15°C, southeast of the modern lake and characterized by Limnocythere sanctipatricti in combination with Cytherissa lacustris. At a later stage the lake probably underwent displacement to the west as a result of continued weak subsidence mainly in the area of the actual lake. The recovery of Cytherissa lacustris together with Limnocythere inopinata but not L. sancti- patricii would indicate warmer conditions during this later stage. It is quite likely that the downward movement may have continued after this period especially in the southwestern portion of the recent lake. So far neither Cyther- issa nor Limnocythere sanctipatricij has been found along the lakes southwestern shore. There are some indications that ostracode materia! of a lacustrine period of the last interglacial time may be present east of Neusiedlersee. However, this remains to be substantiated. BIBLIOGRAPHY Benson, R. H. and MacDonald, H. C. 1963. Postglacial (Holocene) ostracodes from Lake Erie. Univ. Kansas Pal. Contrib., Arthropoda, Art. 4, pp. 1-26. Burger, B. 1964. Results of a pollenanalytic investigation in the Untersee near Lunz in Austria. Geol. Mijnbouw, 43, pp. 94-102. Delorme, L. D. 1969. Ostracodes as Quaternary paleoecological indicators. Canadian J. Earth Sci., 6, pp. 1471-1476. 1971. Paleoecological determinations using Pleistocene freshwater ostra- codes. Bull. Centre Rech. Pau-SNPA, 5 suppl., pp. 341-347. OstRAcopEs ALPINE AND PREALPINE LAKES 443 Frey, D. G. 1955. Ldngsee: A history of meromixis. Mem. Ist. Ital. Idrobiol., suppl. 8, pp. 141-146. 1964. Remains of animals in Quaternary lake and bog sediments and their interpretation. Ergeb. Limnol., Beih. 2, Arch, Hydrobiol., pp. 1-114. Findenegg, |. : ; 1965. Die Eutrophierung des Klopeiner Sees. Osterr. Wasserwirtschaft, 17, pp. 175-181. Gams, H. 1927. Die Geschichte der Lunzer Seen, Moore and Walder. Int. Rev. Hydrobiol., 18, pp. 305-336. Loffler, H. 1969. Recent and subfossil distribution of Cytherissa lacustris, Comm. Int. Ass. Limnol., 17, pp. 240-251. 1971. Daten zur subfossilen und lebenden Ostrakodenfauna in Worther- see und Klopeinersee. Carinthia, Sonderh. 31, pp. 79-89. 1972. The distribution of subfossil ostracods and diatoms in pre-alpine lakes. Int. Ass. Limnol. Trans. 78, pp. 7039-7050. Stiny, J. 1934. Zur Kenntnis der Hochflache von Riickersdorf (Kdarnten). Jahrb. Geol. Bundesanst., Wien, 84, pp. 1-12. Swain, F. M., and Gilby, J. M. 1964. Ecology and taxonomy of Ostracoda and an alga from Lake Nicaragua. Publ. staz. zool. Napoli, 43. pp. 361-381, H. Léoffler, University of Vienna, Vienna, Austria 1099 DISCUSSION Dr. L. D. Delorme: Where do you find Cytherissa lacustris living today? Dr. Loffler: You find it everywhere except in organic ooze. That means, for example, if you think in terms of fecal pellets or if you think in terms of algae which are decomposed and formed of a very fine matter the animals could not waik on it. We have done experiments on this, partly with plastic beads of different grain size as well as with natural substrates. Dr. Delorme: Do you find that Cytherissa lacustris occurs more abundantly or more commonly in lakes that are thermally stratified vs. lakes that are not? What about its occurrence in deep stratified lakes? Dr. Léffler: Oh yes, but it is not such an expressed cold water form like Limnocythere sanctipatricii. It is more sensitive because of the span of its life- time which is certainly 2 years but may be even more than that, but Limno- cythere are much shorter lived species. pee We it he walt , bit mie " ba nes ae Vile bP oye 4 sie 7 7, we |, igure hws sis \ere Conds es aid a9 cnheek ia aaa a nm oyonte 1. ‘sy, na@uvnls j 4 anyysh) as) pris PRR a f] eh a aie Meee ap ee iat) ie ¥ vial ie . ‘ oa > Rs Tang vi ei i heel : ee aie Hed log re Neh ‘ < ‘ BY 5 ue yw 4 he intr faa Ave si biel cM « Wate oa vi im nv ladys aoa AOA iat aa Uy : UTILISATION DES OSTRACODES POUR LA MISE EN EVIDENCE ET L’EVOLUTION D'UNE LAGUNE HOLOCENE A L’OUEST DE LA GIRONDE, GOLFE DE BISCAY PIERRE CaRBONEL, JEAN Moyes, ET JEAN-PIERRE PEYPOUQUET Université de Bordeaux ABSTRACT In a zone of the Bay of Biscay, located west of the Gironde estuary (45°40’N., 1°30’W.) on and about the 50 m depth line, the ostracode faunal associations found in the surficial sediments sometimes show an incompatibility with the present depth of the deposits. Thus are found areas rich in “phytal” and euryhaline species, as well as zones with no ostracodes. The study of cored sediments permitted us to tie in these surface anomalies with the presence of a lagoon which, from C!4 dates, was formed approxi- mately 10,000 years B. P. when the strand line was located at 50 m below present sea level. At this time, to the east of an azoic zone, an euryhaline ostracode associa- tion developed (Cyprideis torosa Jones, Cushmanidea elongata Brady) fol- lowed by a “phytal” association (Paradoxostoma spp. Schlerochilus spp., Hirschmannia spp.). Farther east, the amount of euryhaline species increased, and, in certain limited zones to the northeast and to the south, oligohaline forms (Ilyocypris, Cypridopsis, Candona) increased. The ostracode associations thus permit the reconstitution of different environments in which the salinity varied from west to east with two zones of minimum values, suggesting fluvial deposits. One can thus imagine at 10,000 B. P. the formation of a lagoon behind a dune complex, which was influenced by marine water as well as fresh water brought in by two outlets from the Gironde estuary. Then, during the Holo- cene transgression, the lagoon was submerged and the ostracode associations acquired the characteristics of the present water depth (Loxoconcha guttata (Norman), Carinocythereis sp., Costa edwardsii (Roemer). INTRODUCTION Dans la zone située a |’Ouest de l’estuaire de la Gironde (entre 45°20’ et 46° de latitude Nord et 1° et 2° de longitude Ouest), par des fonds de 20 4 60 m, des campagnes en mer ont permis de recueillir des sédiments 4 la fois par bennes et carottages (Text-fig. 1) qui se sont révélés généralement riches en ostracodes. Les associations fauniques ont été étudiées dans un premier temps dans les matériaux recueillis au niveau du fond et leur répartition a été carto- graphiée. Puis, l|’évolution de ces ensembles a été examinée dans les sédiments carottés, de maniére a déceler les modifications éventuelles dans le temps. Les résultats acquis ont autorisé une utillsation de ces associations dans la reconstitu- tion des environnements successifs de ce domaine durant |’Holocéne. I. OSTRACODES RECUEILLIS DANS LES SEDIMENTS DE SURFACE Parmi les 120 échantillons examinés, les uns sont totalement dépourvus d’Ostracodes, les autres renferment une population riche. Ces microorganismes constituent soit un ensemble homogéne, soit des associations hétérogénes au sein desquelles se trouvent juxtaposés certains groupes dont les caractéres écologi- ques sont difficilement compatibles. Ainsi, nous avons reconnu: 1. Une association “A”, typique de la zone infralittorale interne (M. Vigneaux, et al., 1972), comprenant: 446 CARBONEL, Moyes, AND PEYPOUQUET Radiale septentrionale Carotte Radiale centrale Radiale méridionale RI Sadie Radiale méridionale R 2 des espéces caractéristiques: Loxoconcha guttata (Norman, 1865), Carino- cythereis carinata (Roemer, 1838), Costa edwardsij edwardsii (Roemer, 1838), Eucythere declivis (Norman, 1865), Bythocythere constricta Sars, 1866. des espéces accessoires: Loxoconcha multiflora (Norman, 1865), Lepto- cythere pellucida (Baird, 1850), Leptocythere tenera (Brady, 1867), Carino- cythereis emaciata (Brady, 1867), Cytheropteron crassipinnatum Brady & Norman, 1889. Bay or Biscay HoLocene LAGoon 447 2. Une association ‘“B’’, plus complexe groupant d’une part les formes typiques de l’association “A”, d’autre part les espéces suivantes, qui habitent les algueraies dans les zones a salinité normale (I. Yassini, 1969), avec: des espéces caractéristiques: Semicytherura arcachonensis, Yassini, 1969, S. acuticostata (Sars, 1866), Hemicytherura videns (G. W. Miller, 1894), Microcytherura fulva (Brady and Robertson, 1874), Paradoxostoma sar- niense Brady, 1867, Aurila convexa (Baird, 1850), petite forme, Hetero- cythereis albomaculata (Baird, 1838), petite forme, Pontocypris mytiloides (Norman, 1862). des espéces accessoires: Semicytherura producta (Brady, 1867), S. striata (Sars, 1865), S. angulata (Brady, 1867), Loxoconcha rhomboidea (Fischer, 1855), Propontocypris pirifera (G. W. Miiller, 1894) Sahnia subulata (Brady, 1867), Neocytherideis fasciata (Brady and Robertson, 1874), Hirschmannia tamarindus (Jones, 1856), Paracytherois flexuosa (Brady, 1867), P. producta (Brady and Norman, 1889), P. arcuata (Brady, 1867), Xiphichilus sp. 1, Microcythere sp. I. 3. Une association “C”, trés hétérogéne comprenant 4 types: un groupement de type “A”, un ensemble de formes connues sur les algues dans les zones euryhalines en aval de l’estuaire de la Gironde (P. Carbonel, J. Moyes, J. P. Peypou- quet, 1972), comprenant: des espéces caractéristiques: Paradoxostoma ensiforme Brady, 1867, P. normani Brady, 1867, Sclerochilus contortus (Norman, 1861), Loxo- concha rhomboidea (Fischer, 1855), Cytherois fischeri (Sars, 1866). des espéces accessoires: Semicytherura nigrescens (Baird, 1838), 8S. sella (Sars, 1866), Callistocythere pallida (G. W. Miller, 1894), Hirschmannia viridis (O. F. Miller, 1785), Paradoxostoma bradyi, Sars, 1928. un autre ensemble caractéristique du domaine euryhalin, représenté par: Leptocythere castanea (Sars, 1866), Loxoconcha elliptica (Brady, 1868), Cyprideis torosa (Jones, 1850), Aurila convexa (Baird, 1850), grande forme, Heterocythereis albomaculata (Baird, 1838), grande forme, Cush- manidea elongata (Brady, 1868), Urocythereis oblonga (Brady, 1866). Enfin, quelques espéces typiques d’eaux oligohalines: Candona sp. div., Ilyocypris gibba (Ramdohr, 1808), Limnocythere inopinata (Baird, 1843), Cypridopsis vidua (O. F. Miller, 1776). La répartition des divers ensembles fauniques que nous venons de définir (Text-fig. 2), ne se fait pas au hasard, mais suivant des lois particuliéres. Ainsi, les sédiments dépourvus d’Ostracodes constituent-ils deux domaines alignés parallélement a la cOte actuelle et situés vers les isobathes — 50 m et — 20 m. La faune de type infralittoral interne, qui constitue la totalité de la popu- lation dans deux aires limitées (Text-fig. 2), caractérise bien du point de 448 CaRBONEL, Moyes, AND PEYPOUQUET Sans _ostracodes E=3_~sFaune infralittorale inteme et phytale Faune infralittorale interne RSs Faune infralittorale interne, phytale euryhaline 1g 3 vue bathymétrique la zone considérée. Ailleurs, elle est associée a des groupe- ments soit d’espéces “phytales” sténohalines, soit euryhalines et oligohalines qui sont toutes incompatibles avec la profondeur actuelle du dépot. Dans le matériel examiné, les carapaces et les valves présentent un excel- lent état de conservation, mais en général, les valves translucides ne contiennent pas de restes de l’animal. Si les associations homogénes, de type infralittoral interne, en harmonie avec la profondeur actuelle des dépOts, peuvent étre considérées comme représentatives d’une biocénose, en revanche les ensembles “phytaux”, euryhalins et oligohalins sont soit des formes apportées en suspen- sion par les courants, car les valves fragiles sont trés bien conservées, soit des individus fossiles appartenant alors a un biotope ancien. Bay oF Biscay HoLocene LAGoon 449 Les zones riches en Ostracodes correspondent a des vases et des silts, celles qui en sont dépourvues 4 un substratum de sables le plus souvent éolisés repris ultérieurement par la mer (M. Vigneaux, et al., 1971). Nous voyons donc se matérialiser, cernée par des corps sableux éolisés sans Ostracodes, une zone de vasiére 4 microfaune marine dans la partie centrale et 4 ensemble d’Ostracodes hétérogéne 4 dominante euryhaline dans les zones septentrionale et méridionale. Ce schéma complexe résulte-t-il seulement de lapport actuel d’espéces phytales et euryhalines en provenance de l’estuaire de la Gironde ou de la présence de formes fossiles d’Age holocéne ? L’étude de carottes implantées dans cette zone doit apporter des éléments de réponse. II. LES OSTRACODES DANS LES SERIES CAROTTEES Les associations fauniques d’Ostracodes ont été inventoriées dans les nom- breux carottages (Text-fig. 1) réalisés dans la région considérée. Nous allons les examiner suivant quatre radiales qui nous paraissent apporter les infor- mations les plus précieuses. II-1. Radiale septentrionale (Text-fig. 3). D’Ouest en Est, les séries carottées montrent les associations suivantes: Carotte C 6607 (1,40 m): alternance de sables fins jaunatres et d’horizons sablo-vaseux. Ces derniers renferment une microfaune d’Ostracodes toujours caractérisée par |’association de type “A” précédemment décrite. Carotte C. 6608 (2,20 m): sables jaunes grossiers toujours éolisés a galets et débris coquilliers dans la moitié inférieure, sans Ostracodes. Carotte C. 6903. 3,50 4 3. +m: sables grossiers, éolisés dans la partie supérieure, avec de nombreux galets; dépourvus d’Ostracodes. 3 a 2,10 m: sables coquilliers renfermant une association faunique hétérogéne de type “B’’, au sein de laquelle le pourcentage des espéces marines est important. Présence de quelques formes oligohalines. 2,10 a 1,90 m: dépot sablo-vaseux caractérisé par une association d’Ostra- codes exclusivement marine de type “B”. WENN) ey m: passage graduel de sables fins granoclassés a la base a des vases plastiques gris foncé au sommet. La faune est semblable a celle reconnue entre 3 m et 2,10 m. 1 a0 _ wm: alternance de silts fins sans Ostracodes et de vases silteuses renfermant des associations de types “B” et “C” avec prédominance des formes marines. Carotte C. 7108: 2,10 a 1,05 m: vase caractérisée par l’association “C” a la base et “B” vers le sommet. Mais de nombreux horizons sont dépourvus d’Ostracodes. 1,05 a 0 m: sable trés fin 4 ]a base, puis ensemble silto-vaseux renfer- mant l’association “C” avec des formes marines peu nom- breuses. 450 CARBONEL, Moyes, AND PEYPOUQUET 7009 RADIALE SEPTENTRIONALE 215m @ o o = £ s # are 3 ° @ a ar = wo o Sel cC|l/esspteorvre mAsFtFsz8s © VEE ILIE BAINES _—— — @ C Bay oF Biscay HoLocene LAGOoon 451 Carotte C. 7009 (0,50 m):sables gris, fins et homogénes, parfois éolisés. L’ensemble est azoique, excepté entre 0,30 m et 0,20 m ot la microfaune est euryhaline. Carotte C. 7103 (1,70 m): alternance de sables grossiers sans Ostracodes et de sables fins caractérisés par |’association faunique “C”. Les formes marines sont toujours peu abondantes, tandis que les formes oligohalines prennent localement une certaine importance. Au-dessus de 0,50 m, l’association faunique est largement euryhaline. La comparaison des successions reconnues dans ces diverses coupes nous améne a formuler les remarques suivantes: Les sables éolisés sans Ostracodes reconnus au niveau du fond, existent aussi en profondeus (C. 6608). Ainsi, peut-on estimer que ce type de dépot correspond a |’existence d’un cordon dunaire fossile. Ces sables grossiers se retrouvent dans certaines carottes (C. 6903, C. 7009, C. 7103) a des niveaux de plus en plus proches de la surface du fond au fur et a mesure que l’on se déplace vers |’Est. Ils permettent d’entrevoir l’existence d’une cuvette a flanc abrupt vers — 50 m environ et a pente douce a |’Est. Ce cordon dunaire sépare deux types d’environnement: a |’Ouest un biotope de type infralittoral interne (C. 6607); a VEst un milieu a faune complexe, dominée, de plus en plus nettement en allant vers la zone orientale, par le caractére estuarien (C. 6903, C. 7108, C. 7103). En succession verticale, dans le partie occidentale (C. 6607), la faune marine évolue trés peu. Par contre, a |’Est du cordon dunaire, on observe une modification qualitative et quantitative des associations fauniques dans le temps. Ainsi, dans la carotte C. 6903, la microfaune typique d’un milieu lagun- aire a la base, montre une prédominance du caractére marin au sommet. II-2. Radiale Centrale (Text-fig. 4). Carotte C. 7017 (1,10 m): vases homogénes, trés plastiques dans lesquelles on trouve une microfaune de type “A”, avec localement (vers 0,50 m) un trés faible pourcentage d’espéces phytales sténohalines et parfois euryhalines. Carotte C. 6902: 4,30 a 3,70 m: sables grossiers, roux, souvent éolisés, avec des galets, sans trace d’Ostracodes. 3,70 a 2,50 m: alternances de vase fine et de niveaux silteux 4 nombreux débris coquilliers et traces de bioturbation. L’ensemble fauni- que est caractérisé par |’exceptionnelle richesse qualitative et quantitative de l’association “C”. 2,50 a 1.70 m: vases relativement fines 4 nombreux débris coquilliers. L’ensemble faunique exclusivement marin est de type “B”. 1,70 a 1,30 m: vases avec quelques alternances silteuses. L’association faunique est semblable a celle reconnue entre 3,70 m et 2,5 Onis 1,30 4 0 =m: vases homogénes avec de rares coquilles et les traces de bioturbations; la faune est de type “A”. Une datation au 14 C réalisée entre 3,30 m et 3,10 m a donné un age de 10 000 ans B. P. (M. Vigneaux, ef al., 1971). Carotte C. 7109: 1,80 4 1,10 m: vase plastique homogéne, dont quelques rares niveaux renferment une microfaune d’Ostracodes de type “B”. 1,10 a 0,90 m: sables grossiers avec de nombreuses traces d’éolisation. pas d’Ostracodes. 0,90 4 0 m: vase brune trés plastique et riche en matiéres organiques, renfermant une microfaune de type “A”. CaRBONEL, Moyes, AND PEYPOUQUET 452 wi JIVYLNSO Oe JWIGVY 6012 asiioa [TTT] sapoooijso,p sod [| uljoyob1|0 uljoyaung FES] uljoudine jojkyg WA ul |D4kYg pect ULIDW Eaaly apuebey g Lb0L° 2) Bay or Biscay HoLocenE LAGoon 453 Carotte C. 7110 (1,10 m): sables moyens, jaunes, homogénes et souvent éolisés, dépourvus d’Ostracodes. Dans les sédiments carottés de cette radiale, la faune posséde un caractére marin accusé; les influences estuariennes sont pratiquement inexistantes ainsi qu’en témoigne l’absence totale de formes euryhalines et oligohalines. A lextrémité la plus orientale de la radiale, le dépdt correspond a un ancien “cordon dunaire” (C. 7110) analogue a celui matérialisé par la carotte C. 6608 de la radiale précédente. En succession verticale, la microfaune de la carotte C. 7017 évolue trés peu, comme celle de la coupe C. 6607. En revanche, dans la carotte C. 6902, si la base caractérise un milieu lagunaire, comme la C. 6903, la partie supérieure refléte un environnement marin de type infralittoral interne que l’on retrouve a Est (C. 7109). Enfin, la datation de 10 000 B.P. 4 3,20 m permet d’attribuer aux sédiments de C. 6902 un Age holocéne. II-3. Radiale méridionale 1 (Text-fig. 5). Carotte C. 7017: voir radiale centrale. Carotte C. 6910 (0,90 m): Constituée par un ensemble sableux éolisé, sans Ostracodes. Carotte C. 7001 (0,20 m): ensemble sablo-vaseux renfermant une association de type “C” au sein de laquelle les espéces marines sont en pourcentage peu important et les formes oligohalines toujours présentes. Carotte C. 7005: 1,80 a 1,55 m: vase compacte avec minces lits silteux; |’association faunique de type “C” comprend un pourcentage appréciable d’espéces marines et quelques formes oligohalines. 1,55 4 1,40 m: vase plastique homogéne contenant une association marine de type “B”. 1,40 4 1,20 m: sables fins 4 silts, et intercalations de vases. Association faunique “C” semblable a celle reconnue entre 1,80 et 1,55 m. 1,05 a 1,20 m: sédiments sablo-vaseux renfermant une faune marine de type sy 2 ee 1,05 a 0,65 m: vase plastique, un peu silteuse, correspondant a des dépots sans Ostracodes 4 l’exception d’une association “C” (0,80 a 0,85 m). 0,65 a 0,10 m: vase plastique un peu silteuse et intercalations de sables fins, contenant un ensemble “C” avec un pourcentage im- portant d’espéces marines et localement quelques formes oligohalines. 0,10 a 0 m: vase trés plastique homogéne 4 microfaune marine de type SORA Une data tion au 14 cc entre 1,50 et 1,70 m a donné un age de 6 400 ans B.P. Carotte C. 7028 (1,10 m): sables grossiers éolisés sans Ostracodes. L’examen des faunes d’Ostracodes recueillies dans ces carottes permet de mettre en lumiére les faits suivants: Deux biotopes différents apparaissent: ]’un a l’Ouest (C. 7017) sug- gérant une permanence marine; l’autre a l’Est (C. 7005) a caractére estuarien. Séparant ces deux biotopes, la carotte C. 6910 confirme |’existence du cordon dunaire déja mis en évidence dans la radiale septentrionale. Vers — 20 m, les sédiments éolisés (C. 7028) suggérent l’existence d’une zone dunaire alignée sur celle observée dans la radiale centrale. En tenant compte de la datation au 14 C relative 4 la base de la . 7028 7005 7001 6910 7017 — nN uJ Be apsaeue erred 110m Om RADIALE MERIDIONALE R I ’ Bay or Biscay HoLtocEeNnE LAGOON 455 C. 7005, on peut penser que l’environnement estuarien est relativement récent. II-4. Radiale méridionale 2 (Text-fig. 6). Carotte C. 7114 (1,45 m): composée a la base et au sommet de vases trés plas- tiques et dans la partie moyenne d’alternances de sables et de vases. La faune de type “A” est présente seulement dans les vases. Carotte C. 7005 (1,80 m): voir II-3. Carotte C. 7112 (0,65 m): la base et le sommet se composent de vases sableuses comprenant la faune de type “C” rencontrée dans la carotte C. 7005. La partie moyenne est constituée de sables jaunes grossiers et dépourvus d’Ostracodes. Carotte C. 6908 (0,20 m): vase sableuse compacte renfermant une faune pauvre de type “C”. Carotte C. 7007 (1,05 m): galets 4 la base, surmontés de sables partiellement éolisés. Seuls les horizons sommitaux renferment quelques Ostracodes eury- halins. Nous pouvons distinguer selon cette ligne: — un domaine Sud-Ouest (C. 7114) 4 faune typique de la zone in- fralittorale interne. — un domaine Nord-Est (C. 7005, C. 7112, C. 6908) ot la faune présente un type estuarien sur toute l’épaisseur des sédiments. — un cordon dunaire (C. 7007), déja matérialisé (C. 7110, C. 7028) vers — 20 m. Les informations fournies par ces deux derniéres radiales semblent indiquer le passage direct a travers un cordon dunaire (C. 6910, C. 7028), d’un estuaire a la mer. II-5. Si nous synthétisons les observations analytiques relatives a chaque radiale, nous pouvons formuler les conclusions suivantes: Il existe suivant une coupe verticale une succession d’associations fauniques d’Ostracodes semblable a celle observée en surface depuis la zone centrale a microfaune marine homogéne jusqu’aux parties septentrionale et méridionale dans lesquelles |’ensemble faunique est complexe. Les sédiments de surface éolisés, dépourvus d’Ostracodes, se poursuivent en profondeur. Ce phénoméne d’éolisation prouve que ces sables étaient émer- gés avant la transgression holocéne et appartenaient vraisemblablement a des dunes. Ces derniéres semblent avoir formé une barriére importante a la transgression marine vers |’isobathe — 50 m (C. 6608, C. 6910), puis vers — 20 m en face de l’embouchure de la Gironde actuelle (C. 7110, C. 7109, C. 7007, C. 7028). Les sédiments éolisés ont aussi été reconnus en carottes, sous une épaisseur plus ou moins grande, entre les cordons dunaires de — 50 m et — 20 m. Ceci tend a prouver l’existence d’une cuvette cernée par les dunes. A VOuest du cordon dunaire de — 50 m, se rencontre (C. 6607, C. 7017, C. 7114) une microfaune homogéne “A”, typique d’un milieu infralittoral interne. A l'Est et au Nord de ce méme cordon, le caractére marin de la microfaune tend a s’estomper progressivement. Ainsi, dans la carotte C. 6902, ]’association faunique est toujours marine; ce caractére est encore bien marqué dans la coupe C. 7109, mais il devient plus difficile 4 discerner dans le domaine plus oriental (C. 7108). Au Nord, les Ostracodes montrent toujours la dualité des influences marines et estuariennes (C. 6903). Toutefois, le cachet marin est prédominant. Dans le partie méridionale, il semble que nous soyons a proximité d’une embouchure de fleuve, car nous avons un passage rapide du milieu marin 456 CaRBONEL, Moyes, AND PEYPOUQUET 7007 3.086 eo 0 @ eeesence eeecsoee ceeeeeee io @ eo ee RADIALE MERIDIONALE Re 7112 7905 7114 Bay oF Biscay HoLocene LAGoon 457 (C. 7114) a un milieu estuarien. En effet, la carotte C. 7005 offre une faune complexe au sein de laquelle se manifeste constamment le conflit entre les influences marines et fluviatiles. D’une maniére schématique, la succession verticale des faunes indique un caractére marin de plus en plus franc au fur et a mesure que l’on se rapproche de la période actuelle. Le passage de l’environnement laguno-marin 4 celui de mer ouverte est particuliérement net et rapide dans la partie centrale (C. 6902). Cette évolution est moins marquée dans les zones septentrionale et méridionale et estompée prés de la surface par la présence d’ensembles fauni- ques euryhalins incompatibles avec la position du prélévement. Nous sommes donc amenés a penser que ce domaine a évolué par étapes depuis un environnement continental et fluviatile jusqu’au domaine marin actuel. L’4ge de 10 000 ans donné par le 14 C nous permet de situer de début de cette histoire a |’Holocéne. III. EsSAI DE RECONSTITUTION PALEOGEOGRAPHIQUE Il est alors tentant de voir ce que la seule étude des Ostracodes peut apporter dans une reconstitution des paléogéographies successives de la zone considérée durant |’Holoceéne. x III-1. Si nous considérons la région a une période antérieure a 10 000 ans B.P., nous avons peu d’informations. En effet, seuls les sédiments de la C. 6902 (3,70-3,50 m) renferment des microorganismes marins de type infra- littoral interne et phytal, et |’analyse lithologique montre que les sédiments de base suggérent un delta de marée (M. Vigneaux ef al., 1971). A l'Ouest, le long de l’isobathe actuel — 50 m, les sables roux, grossiers, souvent éolisés, avec de nombreux débris coquilliers traduisent des milieux de plages en avant des cordons dunaires (C. 6910, C. 6608). Dans la région la plus occidentale, on note la permanence d’une faune marine typique d’un plateau continental sableux (C. 7017, C. 7114). On peut donc imaginer (Text-figs. 7) qu’avant le début |’Holocéne le rivage marin se situait vers — 50 m. En arriére de la plage, des dunes, semblables a celles du littoral aquitain actuel dessinaient des reliefs de faible amplitude. Un fleuve, qui se marque dans les sédiments par un delta de marée, atteignait directement la mer a travers les dunes. Vers |’Est, une plaine alluviale pouvait s’étendre en avant d’un second cordon dunaire situé aux environs de la cote — 20 m. III-2. Avec le début de l’Holocéne, la transgression flandrienne se poursuit en occupant la zone située immédiatement a I’Est de la barriére sableuse et donne naissance dans la partie centrale 4 une lagune marine. En effet dans la carotte C. 6902, on rencontre les formes caractéristiques du biotope phytal sténohalin associées aux formes d’origine océanique et a celles qui sont caractéristiques des biotopes sableux euryhalins. D’un point de vue qualitatif et quantitatif cette microfaune d’Ostracodes ressemble a celle signalée par I. Yassini (1969) dans les chenaux du bassin d’Arcachon. Ainsi, peut-on penser que la faune de cette carotte est le témoig- 458 CaRBONEL, Moyes, AND PEYPOUQUET Phase TI Avant 10000 ans BP nage d’un environnement de chenal peu profond a substrat sablo-vaseux, tapissé par les algues et largement alimenté par ]’onde marine avec une salinité allant de 30 a 33%. Dans la carotte C. 6903, les associations fauniques complexes de type “C” sont caractérisées par l’importance des formes euryhalines et la présence d’espéces oligohalines. Elles attestent ainsi du débouché d’une riviére dans une lagune (Text-fig. 8), dont l’extension est difficile 4 préciser: néanmoins, on peut la reconnaitre a |’Est jusqu’aux carottes C. 7108 et 7109 et au Nord, au-dela de la carotte C. 6903. III-3. Puis dans une étape ultérieure, la mer déborde les cordons dunaires occidentaux et modifie complétement (Text-fig. 9) le paysage précédent selon le schéma suivant: Dans le secteur central (carottes C. 6902, C. 7109) il y a passage rapide et sans transition de |’état lagune marine a celui de mer ouverte. On constate en effet un rapide déclin des formes phytales au profit des espéces marines de |’association “A”. I] est évident que l’augmentation rapide de la tranche d’eau qui occupe cette région a pour conséquence de faire péricliter les algueraies qui s’étaient développées, et par la-méme les Ostracodes qui vivaient. Ce fait semble en accord avec le taux de remontée important du niveau marin mis en évidence par A. Feral, (1970) entre 10 000 et 7 000 ans B.P. environ. De plus, on constate que la granulométrie de ces carottes devient 459 Bay or Biscay HoLocene LAGoon Phase II Vers 10000 ans BP. pag Phase Vers 7000 ans B.P. 460 CaRBONEL, Moyes, AND PEYPOUQUET de plus en plus fine. Une “vasiére” se forme donc trés rapidement et fonctionne en tant que telle, probablement vers cette derniére date. L’absence de formes euryhalines et oligohalines dans ce secteur peut s’expliquer par le fait que le cordon dunaire Est (C. 7110, C. 7009) protégeait la lagune des arrivées d’eau douce. Au Nord et au Sud, la microfaune d’Ostracodes présente des similitudes que traduit la présence de formes euryhalines et oligohalines. Ces formes sont les témoins des environnements “estuariens” qui se sont établis alors. Dans le secteur septentrional, les plus anciennes empreintes de ce type d’environnement sont situés a4 l’Ouest (partie moyenne et supérieure de la carotte C. 6903) puis vers l'Est (carotte C. 7108 et C. 7103). On y reconnait notamment les espéces des biotopes phytaux euryhalins semblables 4 ceux qui existent actuellement dans la partie aval de la Gironde entre la Coubre et Talmont (P. Carbonel, J. Moyes, J. P. Peypouquet, 1972). Ce fait implique, que durant cette phase, et sur la trajectoire Ouest-Est définie ci-dessue, existaient des milieux euryhalins estuariens dont la salinité évoluait de 15 a 28% pour les zones les plus continentales 4 28%-33% pour les plus marines. Il est difficile de dater avec précision cette étape dans |’Holocéne. Toutefois, en reprenant l’hypothése précédemment émise par Feral, 1970 sur l’évolution de |’estuaire de la Gironde, on peut considérer qu’il y a environ 10 000 ans B.P., ce fleuve avait un régime dit 4 méandres. A partir de 10 000 ans B.P. par suite du taux de remontée du niveau marin particuliérement élevé (1,50 m par siécle en moyenne), le régime fluvial va se transformer compléetement et devenir de type estuarien vers 7 000 ans environ. On peut donc admettre cette date pour |’établissement d’un estuaire dans cette zone. Dans le secteur méridional, on constate l’absence de lagune marine. La zone de plate-forme continentale (C. 7114) communique avec une zone estuarienne trés complexe (C. 7005) située au milieu d’un “couloir” dunaire (C. 6910, C. 7028). L’établissement de ce paysage date de 6 400 ans B.P. (Text- fi See55 6) L’absence de faune d’age antérieur 4 6 400 ans B.P. dans cette région peut s’expliquer par le fait que nous sommes dans une zone de passage fluvia- tile relativement étroite (“couloir” dunaire, C. 7007, C. 7005, C. 7028). Ceci implique une mobilité des fonds incompatible avec |’établissement de biotopes phytaux fayorables au développement des Ostracodes, ou avec le dépot de microfaune transportée. De la méme maniére que dans le secteur septentrional, on peut suivre le déplacement de ce type d’environnement dans les carottes C. 7112 et C. 6908 en direction de l’estuaire actue] de la Gironde. Mais, il est fort possible que le raccord ait pu s’effectuer avec les passes fossiles du chenal de Soulac datant de 6 000 ans B.P. signalé par A. Feral, (1970). Que ce soit dans le secteur septentrional ou dans le secteur méridional, on constate ]a permanence du type estuarien tout le long des carottes C. 7005, C. 7013, C. 7108, C. 7112 et seule une faible épaisseur de sédiments au sommet de celles ci présente ume faune au caractére marin infralittoral interne. Bay oF Biscay HoLocENE LAGOON 461 I] semble que ce phénoméne puisse expliquer dans une certaine mesure le fait qu’a partir de 5 000 ans B.P. le taux de remontée du niveau marin est inférieur 4 0,25 m par siecle (A. Feral, 1970), ceci implique donc une évolution lente et un passage trés graduel du régime estuarien au régime marin pour cette zone. III-4. Dans une derniére phase, la mer franchit le cordon dunaire de -— 20 m (carottes C. 7007, C. 7110, C. 7028) et repousse vers l’Est les domaines estuariens. En effet, la faune marine infralittorale interne “A”, marquée toutefois par des apports euryhalins actuels en provenance de la Gironde (P. Carbonel, 1971), s’installe alors dans les secteurs septentrional et méridional de la zone étudiée. Finalement, l’onde marine atteint le littoral aquitain (Text-fig. 10) entaillé par un nouvel et unique estuaire entre Royan et le Verdon. C’est l’époque actuelle. BIBLIOGRAPHIE Carbonel, P. 1971. Les ensembles fauniques d’Ostracodes récents de l’estuaire de la Gironde et du proche plateau continental. Relations avec les phénoménes hydrodynamiques. Intérét dans la reconstitution des paléoenvironnements. Thése 3¢me Cycle. Univ. Bordeaux I, 209 pp eV pli 37, tise Carbonel, P., Moyes, J. et Peypouquet, J. P. 1972. Ostracodes du domaine phytal intertidal dans la partie aval de Vestuaire de la Gironde et dans la zone N.W. de Vile d’Oléron. Bull. Inst. Géol. Bassin d’Aquitaine, Bordeaux. Vol. 12, pp. 191-194. 462 CaRBONEL, Moyes, AND PEYPOUQUET Feral, A. 1970. Interprétation sédimentologique et paléogéographique des forma- tions alluviales flandriennes de Vestuaire de la Gironde et de ses dépendances marines. Thése 3éme cycle. Univ. Bordeaux I, 158 pp., 62 fig., 2 tabl. Vigneaux, M. 1971. Bilan d’étude d’environment marin et applications dans le Golfe de Gascogne. Colloque International sur l’Exploitation des Océans, Bordeaux (France), Mars 1971, CNEXO Paris, Theme III, tome 2, G. 1 05, 66 pp., 29 fig., 5 tabl. 1972. Bilan cartographique des études effectuées sur le plateau contin- ental aquitain au 28 Février 1972 par l'Institut de Géologie du Bassin d’Aquitaine. Bull. Inst. Géol. Bassin d’Aquitaine, Bordeaux, No. Spécial, 1972, 25 pp., 5 figs., 13 cartes h.t. Yassini, I. 1969. Ecologie des associations d’Ostracodes du Bassin d’Arcachon et du littoral atlantique. Application a l’interprétation de quelques populations du Tertiaire aquitain. Bull. Inst. Géol. Bassin d’Aqui- taine, Bordeaux, No. 7, 1969, 288 pp., 39 pl., 3 fig., 54 tabl. Pierre Carbonel, Jean Moyes, et Jean-Pierre Peypouquet, Laboratoire de Géologie et Océanographie Université de Bordeaux I, Talence, France. DISCUSSION Dr. J. C. Kraft: The Holocene environmental reconstructions are very impres- sive. I am interested in a detailed listing of the supporting ostracode faunas. Are they available in the paper to be published? Authors’ reply: The species from the various environments are in the text. Dr. H. Léffler: Are ostracodes absent from the eolian sands since transparency at that depth still would provide for algae attached to sand grains? Authors’ reply: At the bottom, the eolian sands are relatively fine-grained (1 mm) which is not favorable to the installation of algal biotypes, and hence phytal ostracodes. Moreover these sediments contain no silt and clay. Hence, there is no layer of organic matter and mud on the bottom. Therefore, continental shelf ostracodes of the internal-infralittoral zone can’t develop. These eolian sands represent ancient shore sands which were constantly reworked by tides. Ostracodes could not live in this unstable substrate. Dr. G. Hartmann: As far as my experience goes, the shore sand is not at all populated by ostracods because of the movement of the sediments only the interstitial system is populated. Authors’ reply: We are of the same opinion as Dr. Hartmann. The coastal sands of the Bay of Biscay contain no ostracodes. OSTRACODE BIOFACIES IN THE CAPE HATTERAS, NORTH CAROLINA, AREA JosepH E. Hazei* U. S. Geological Survey ABSTRACT Thirty-eight samples spaced on a grid around Cape Hatteras at depths of 15 to 90 meters contain a total of 126 species of ostracodes. The comparison of these samples on the basis of the presence and abundance of the species, using a multistate quantitative measure and principal coordinates analysis, allows the recognition of three biofacies and the position of the boundary between the Virginian and Carolinian faunal provinces. A Carolinian bio- facies is present in the vicinity of Cape Hatteras in northern Raleigh Bay, on Diamond Shoals, and immediately east and north of the cape. The second bio- facies assigned to the Carolinian Province occupies eastern and southern Raleigh Bay. A third biofacies is assigned to the Virginian Province and is found north and northeast of Cape Hatteras. The principal control on the major faunal discontinuity appears to be summer bottom temperature; the boundary between the provinces closely approximates the 22.5°C and 25.0°C isotherms for the warmest month. BIOFACIES D?OSTRACODES AUX ENVIRONS DE CAPE HATTERAS, CAROLINE DU NORD RESUME Trente huit échantillons pris a des profondeurs de 15 a 90 métres, a distance réguliére l’un de |’autre aux environs de Cape Hatteras contiennent au total 126 especes d’Ostracodes. La comparaison de ces échantillons en con- sidérant la présence et |’ abondance des especes et en utilisant de coéfficient de corrélation (r) et l’analyse des coordonnées principales, permet de recon- Nnaitre trois biofaciés et de tracer la frontiére entre les provinces fauniques virginienne et carolinienne. Un premier biofacies carolinien a été trouvé aux environs de Cape Hatteras, dane la partie nord de Raleigh Bay, 4 Diamond Shoals, et immédiatement 4 l’est et au nord de Cape Hatteras. Un second bio- faciés appartenant a la province carolinienne se trouve dans la partie est et sud de Raleigh Bay. Le troisiéme biofaciés qui fait partie de la province vir- ginienne a été retrouvé au nord et au nord est de Cape Hatteras. La discon- tinuité faunique parait €étre occasionée principalement par la température estivale des fonds marins: les différentes provinces se touchent sur les jso- thermes de 22.5°C et 25°C du mois le plus chaud. INTRODUCTION It has been known for many years that in the Cape Hatteras, North Caroline, area (Text-fig. 1) many benthic invertebrates cease their equatorward or poleward expansion. Cape Hatteras has been designated a boundary between two faunal provinces by several authors (Hazel, 1970a, for a review). The most consistently used terminology for these provinces is Carolinian for the area south of the Cape and Virginian in the area to the north; the terms were first proposed by Dana (1953a,b). Until recently no attempts were made to determine the configuration on the continental shelf of this provincial boundary. The primary purpose of the present paper is to document the distribution of similar ostracode assemblages on the continental shelf; similarity in this *Publication authorized by the Director, U.S. Geological Survey. 464 J. E. Hazev 76° NAY | 3S N pte \ Sound 36°F + Ocracoke Inlety 25 KILOMETERS CONTOURS IN METERS Text-figure 1. — Location of the 38 collecting stations in the Cape Hat- teras, North Carolina, area. Black dots, samples relatively rich in ostracodes; ccircled dot, ostracode density low; circled cross, samples barren. The near- share area between Cape Hatteras and Cape Lookout is Raleigh Bay. Onslow Bay is the next embayed area to the south. case is determined by utilizing counts of the species and a multistate quantita- tive similarity measure. Cluster (in R-mode) and principal coordinates analysis (in Q-Mode) were used to analyze the similarity matrices. Three major biofacies have been delineated using 38 samples containing 126 species (Text- fig) 1 table 1 table 2): A secondary aspect of the study was to see if the patterns of biofacies could be related to macroenvironmental factors. It is shown that the major faunal boundary in the area is related to the distribution of summer bottom temperature. A list of the more important species found in the study area is included. Care Hatreras OsTRACODE BIOFACIES 465 ACKNOWLEDGMENTS I am indebted to P. C. Valentine, U.S. Geological Survey, who in 1969 and 1970 collaborated in the identification of the ostracodes from most of the samples used in the present study as well as others from the Atlantic shelf (Valentine, 1971). I also thank R. H. Benson and M. A. Buzas of the Smithsonian Institution for critically reading the manuscript. RECENT PREVIOUS WORK Cerame-Vivas and Gray (1966), utilizing marine macroinvertebrate oc- currences in samples primarily from immediately south and north of Diamond Shoals and northeast of Oregon Inlet, qualitatively recognized three faunal areas near Cape Hatteras which they termed simply A, B, and C. Their area A, on the middle and inner shelf north and east of the cape, they considered to be inhabited by a southern extension of the arctic and boreal fauna. They also place their area A in the Virginian Province. (These two statements are incompatible; the Virginian Province is really climatically mild temperate, see Hall, 1964; Hazel, 1970a). Their area B, middle and inner shelf south of the cape, is one of “. . . mixed fauna which may receive components from the northern waters of area A and the tropical waters of area C, the latter being the larger contributor . . . there are other species characteristic of B itself,’ (Cerame-Vivas and Gray, 1966, p. 264). Cerame-Vivas and Gray pointed out that under certain winter wind conditions, cool waters of the Virginia Coastal Current penetrate into inshore Raleigh Bay and even into adjacent Onslow Bay. In such a situation, temporary populations of cryophilic species with planktonic larvae may appear in Raleigh Bay. Cerame-Vivas and Gray suggested that area B represents the Carolinian Province, and area C, on the outer shelf east and southeast of the cape, represents a northern extension of the “tropical” Gulf of Mexico and Caribbean fauna. Maturo (1968), in a study of the bryozoans of the Atlantic shelf and slope, recognized two principal biofacies in the Cape Hatteras area. North and northeast of the cape he placed assemblages in the Virginian Province with essentially the same map configuration as that shown by Cerame-Vivas and Gray (1966). South of Cape Hatteras he was not able to differentiate two biofacies and recognized the Carolinian Province and Tropical Province. Maturo noted that 76 percent of the shelf bryozoans south of Cape Hatteras seem to reach their northern limit in the cape area. Using data given by Cerame-Vivas and Gray (1966), he calculated that 74.4 percent of the benthic invertebrates they studied that live south of the cape also ceased their north- ward expansion in the area. Schnitker (1971) studied foraminifer assemblages in the cape area and concluded that the shelf assemblages of Raleigh Bay are intermediate in com- position between those known from north of Cape Hatteras and those from farther south on the shelf. On the basis of dominant species he recognized nearshore, central shelf, and shelf edge-upper continental slope facies north 466 Jey. daze. of the cape in the southern Virginian Province, and central shelf and shelf edge-upper slope facies south of the cape. Immediately south of the present study area, Day, Field, and Montgomery (1971) studied the benthic organisms collected from 10 stations in a southeast- trending transect across the shelf from the shoreline near Cape Lookout to a depth of 200 meters. They visited each station five times, took 85 samples, and compared the stations using multivariate techniques. They recognized an off- shore fauna and an inshore fauna; the latter is best represented at depths of 10 to 20 meters. Between 20 and 39 meters, a marked faunal change was noted; an outer sheif fauna is developed at depths of 40 to 120 meters; an upper slope fauna is present below 140 meters and is best represented at depths of 160 to 200 meters. Day, Field, and Montgomery attributed the in- shore-offshore faunal change to the effects of instability of temperature and water movements caused by waves inshore compared with the relative stability of these factors at offshore depths. It is interesting to note that Day and others did not corroborate the conclusion of Cerame-Vivas and Gray (1966), that the outer shelf assemblages represent the Caribbean Province. They found no obvious biogeographic differences that could not be attributed to local conditions. Valentine (1971) and Hazel (1971) divided the Atlantic shelf from New Jersey to South Carolina into four major biofacies, using a cluster analysis technique and presence-absence data for 159 species of ostracodes in 115 samples. Three biofacies were recognized in the Cape Hatteras area; two of these, their biofacies 2 and 4, were thought to be thermally controlled, whereas the composition of biofacies 3 in the immediate vicinity of Cape Hatteras and disjunct to the south was believed to be related to other physical factors. The present study is an extension of this work in which the number of individuals per species was determined for the samples in Cape Hatteras area, and several samples were added. DESCRIPTION OF THE AREA Geography. — The area of this study comprises the Atlantic shelf off North Carolina from the latitude of Albemarle Sound to that of Cape Lookout and between the 15- and 90-meter isobaths. This is an area of approximately 10,000 km? (Text-fg. 1). Off the two capes in the area, Hatteras and Lookout, are extensive shallow areas termed Diamond Shoals (off Hatteras) and Cape Lookout Shoals. The area between the two capes is Raleigh Bay. At Cape Hatteras the shelf is at its narrowest point on the coast of the United States north of 27°30’N. The change from shelf to slope varies from 60 to 100 meters depth in the area, being shallowest east of Cape Hatteras. W ater-Masses.— The following is summarized from Bumpus (1955) and Stefansson, Atkinson, and Bumpus (1971). Four water masses have been recog- nized in the general area. These have been termed Virginian Coastal Water, Carolinian Coastal Water, Carolinian Slope Water, and Gulf Stream Water. Care Hatteras OsTRACODE BIOFACIES 467 Virginian Coastal Water is thought to be composed of an admixture of slope water and river effluents from areas north of Cape Hatteras, Carolinian Coastal Water is warmer and somewhat more saline and is composed of an admixture of effluents from streams south of Cape Lookout and of Gulf Stream Water. The middle and inner shelf waters of Raleigh Bay may represent Virginian or Carolinian Coastal Waters or an admixture of these depending on seasonal circulation patterns. Gulf Stream Water occupies the outer shelf area and the area seaward of the shelf-slope break south of Cape Hatteras in the study area. Gulf Stream Water is warmer, more saline, and nutrient-poor, relative to coastal water. Underlying Gulf Stream Water on the slope and at times penetrating onto the shelf is Carolinian Slope Water. This water is colder than Gulf Stream Water and summer coastal water and is relatively oxygen-poor. It is thought to be of Caribbean origin. Circulation.— Cape Hatteras is the focal point of the southerly flowing Virginia Coastal Current and the northerly flowing Carolina Coastal Current. Bumpus and Lauzier (1965) indicated that in spring, summer, and fall there is a southerly flow of water in inshore Raleigh Bay. This water is from the southerly flowing Virginia Coastal Current, and Stefansson, Atkinson, and Bumpus (1971) predicted that the maximum intrusion of Virginian Coastal Water into Raleigh Bay would be in Jate summer and spring when runoff from the northern rivers is greatest and when there is a concomitant period of north- easterly winds. The flow of Virginian Coastal Water into Raleigh Bay is weakened by southwesterly winds. Winds in the area are predominately from the south and southwest and from the northeast to northwest. Swells are dominantly from the northeast and east (U.S. Congress, House of Representa- tives, 1948; U.S. Army Corps Engineers, 1964). Von Arx (1962, p. 344) discussed the vagaries in position of the Florida Current in the Cape Hatteras area. He pointed out that the position of the current maximum can oscillate offshore for a period of days, then approach the coastline, covering as many as 35 miles in 4 days; it then retreats to its mean position in 3 to 4 days. When the core of the current moves toward shore, so does a field of sloping isotherms. Water near the bottom can be left be- hind as the current retreats (von Arx, 1962; Blanton, 1971; Stefansson, Atkinson and Bumpus, 1971). The last authors considered the source of this water to be the Caribbean water mass underlying the Florida current and stated that the intrusions are partly wind controlled and favored by southerly or southwesterly winds as well as by stratification. Temperaiure.— Northerly flowing warm currents and southerly flowing cool currents meet at Cape Hatteras. Thus, along the North Carolina coast from Bogue Island to Cape Hatteras, a distance of 50 statute miles, the average surface temperature for February changes from about 10°C to 15°C (Schroeder, 1966). In contrast, along the Atlantic Coast of Western Europe in February it averages 10°C at Brest, France, and 15°C at Tangier, Morocco, a distance of 1400 miles (data from Defant, 1961). 468 J. E. Hazex The confluence of cool and warm currents in the Cape Hatteras area precludes the development on the American Atlantic Coast of a climate even roughly similar to the classic warm-temperate zone of the eastern North At- lantic. That zone is inhabited by the assemblages of the Lusitanian faunal province which is found in the western Mediterranean and along the Atlantic Coast of the Iberian Peninsula and southwestern France. This fact has been often ignored, with the result that the southeastern coast of the United States has been referred to as warm temperate (for example, Johnson, 1934; Stephen- son and Stephenson, 1954). Dana (1853a, b) placed his Carolinian Province in the warm-temperate zone; however, he was well aware of the pinching out of eastern Atlantic climatic regimes. He recognized a five fold division of the temperate zone, and his warm-temperate zone would be referred to as subtropical or outer tropical by most (for example, Hall, 1964). Valentine (1971) and Hazel (1971) indicated that a warm-temperate climate existed along the Middle Atlantic Coast during late Pleistocene and the Miocene- early Pliocene time. In the study area during the warmest time of the year, August-September, the surface temperatures average between 25°C and 28°C (Schroeder, 1965; Walford and Wicklund, 1968). During the coldest month, however, the range in temperature of surface water over the shelf is much greater, being as low as 7.5°C in the north and as high as 20°C in Raleigh Bay. Bottom temperatures, of course, are more important in understanding the distribution of benthic organisms. Recently, Walford and Wicklund (1968) presented bottom-temperature maps for the most of the Atlantic shelf. These authors constructed vertical monthly temperature profiles across alternate quarter degrees, plotting the averages for standard depths at the center of each quarter-degree square. The bottom temperatures were estimated from the monthly profiles, and maps with isotherms in 2.5°C intervals were drawn. The maps represent the only bottom temperature data available in a con- densed form covering an extended period of time (50 years). Text-figures 2 and 3 are bottom-temperature maps based on the average for the coldest and warmest month at each of the 38 stations of the present study. The data were taken from the 12 bottom-temperature maps of Walford and Wicklund (1968), placed on the sample base map (fig. 1), and contoured. These maps should be more useful in interpreting the distribution of organisms than maps for particular months. The periodic influx of cooler Virginian Coastal Water into Raleigh Bay is not evident on these maps or on the surface-temperature maps provided by Schroeder (1966). The surface-temperature maps by Walford and Wicklund (1968, pls. 2, 3) for February and March, however, do show some indication of this. Occasionally, under the influence of persistent northeast winds, the temperatures in Raleigh Bay can become abnormally quite low. Stefansson and Atkinson (1967, p. 7, figs. 14, 20) indicated that in late February and early March of 1966, bottom temperatures in inshore Raleigh Bay averaged between about 5°C and 10°C. However, it was 20°C at one of their stations in outer Care HatreraAs OsTRACODE BIOFACIES 469 Text-figure 2. — Distribution of winter bottom temperature. Based on coldest monthly average bottom temperature at each station. Data from Wal- ford and Wicklund (1968). Sample stations explained in Text-figure 1. Raleigh Bay. The occasional influx of cooler waters into Raleigh and even Onslow Bay apparently allows some cryophilic species with planktonic larval stages to establish themselves outside their normal ranges (Wells and Gray, 1960; Cerame-Vivas and Gray, 1966). It is doubtful, however, if benthic species without planktonic larvae, such as ostracodes, could take advantage of short-term events such as this. Bottom sediment.— Milliman (1972), Milliman, Pilkey, and Ross (1972), Milliman, Pilkey, and Blackwelder (1968), have indicated on a series of maps. the major sedimentary patterns on the shelf in the present area of study. The samples used by those authors are in part the same as those used in the present study. Milliman (1972) classified the bottom sediments seaward of Ocracoke Inlet and on Diamond Shoals as of questionable modern fluvial origin; the rest of the surficial sediments in the area are considered to be relict Pleistocene 470 ee at a = sear a q UM F253 oN 7 57, ye | VL, j cave | © At | © =a We @ © J Fos 0 Zi ; f If = oy is iy | PA | Vi J Text-figure 3.— Distribution of summer bottom temperature. Based on warmest monthly average bottom temperature at each station. Data from Wal- ford and Wicklund (1968). Sample stations explained in Text-figure 1. and of continental origin. North and east of Cape Hatteras and over most of inner and central Raleigh Bay there is less than 5 percent carbonate in the sand- sized fraction. In southern and eastern Raleigh Bay, the carbonate percent increases to 5-25, with patches of higher percentages. In northern and eastern Raleigh Bay, the non-carbonate fraction is composed of subarkosic quartz sands; more orthoquartzitic sands predominate in southern Raleigh Bay. Grain size of the bottom sediment is generally thought of as an important factor in influencing the composition of benthic assemblages. Data on the weight percent of material in each sediment-size grade from Phi 17 to Phi -10 for each sample are given by Hathaway (1971). These data have been grouped herein in the following manner: Gravel =< CC = > id) mir Coarse sand @ = 0-1.0 = 0.5-1.0 mm Medium and fine sand @ = 1.5-3.0 = 0.125-0.49 mm @ = 3.5-4.0 = 0.0625-0.1249 mm Very fine sand 0 = > 4.0 = < 0.0625 mm Silt and clay Care HatTreras OsTRACODE BIOFACIES 471 The weight percents for each of these modal-size classes were normalized by taking the arcsin of the square root of the percentage and multiplying by two. Each station was then compared on the basis of the represented size- classes using the correlation coefficient (r) as a similarity measure and clustered by the unweighted pair-group method. The major clusters in the resulting dendrogram (Text-fig. 4) delineate grain-size bottom facies that can be mapped (Text-fig. 5). A principal components analysis of the same data resulted in essentially the same grouping of samples with 88 percent of the variation explained in the first two dimensions. Diamond Shoals and the shelf immediately east of Cape Hatteras are covered by very fine sands (47 to 72 percent by weight) with very significant percentages (26 to 49) of medium and fine sand (cluster A in fig. 4; fig. 5). Cluster B is composed of the only two samples studied with significant amounts of silt and clay (16 to 24 percent) ; however very fine sand predominates (61- 82 percent). One of these samples was taken at the shelf edge east of Cape Hatteras and the other in Raleigh Bay off southwestern Hatteras Island. Inshore Raleigh Bay and Cape Lookout Shoals contain areas where coarse sand predominates (cluster F). Another area of coarse sand is off northern Hatteras Island. Large areas where coarse sand is mixed approximately equally with medium and fine sand (cluster E) are present in inshore Raleigh Bay, on Cape Lookout Shoals, and on the inner shelf north of Cape Hatteras. Patches of this sediment facies occur on the outer shelf south and north of Cape Hatteras. Most of Raleigh Bay and the shelf north of Cape Hatteras is covered with medium and fine sand (cluster C). SAMPLING The material used in this study was collected as part of the U.S. Geological Survey-Woods Hole Oceanographic Institution program to study the Atlantic continental margin. The 38 samples were taken on cruises of the R/V Gosnold (most samples) and R/V Asterias (a few of the shallower stations). Most of the sampling was done with a Campbell grab, which covers a bottom area of 0.6 square meters. The Asterias samples were taken with a smaller Smith- McIntyre grab. This material was subsampled for ostracodes and foraminifers and the sediment placed in alcohol or buffered formaiin with Rose Bengal. Amounts of wet sediment varying from 30 to 200 cubic centimeters were screened on a 0.084 mm screen and dried. The carbonate part of the sand- sized fraction was separated, using a soap-float technique. The ostracodes were then picked from splits of the float. Four of the samples were barren (Table 1). All identifiable carapaces and valves of adults and juveniles were counted. Because the samples were taken at different times of the year and in different years and because a biogeographic rather than ecologic interpretation was the goal, living and dead were counted together. Fossils were found in some samples; however, they were in general obvious because of what taxa SIMILARITY COEFFICIENT (r) DI ID a=". ra A a. SL 1.00 0.80 0.60 0.40 0.20 0.00 -0.20 2324 2323 1858 2322 1434 1443 1870 1432 1433 2321 1869 1440 1439 1863 2064 1441 1859 1872 1436 1442 1430 1873 1431 1438 1866 1437 2317 2065 1871 2320 1435 2319 1860 1874 1861 2325 2318 2316 Text-figure 4.— Cluster analysis of the 38 stations using weight percents of modal grain sizes as variables. Grain-size data from Hathaway (1971) grouped as indicated. The correlation coefficient (r) was used as a similarity measure. Clustering was by the unweighted pair-group method. The weight percents were normalized by taking the arcsin of the square root of the per- centage and multiplying by two. The clusters labeled A through F are mapped in figure 5. Carr Hatreras OsTRACODE BIOFACIES 473 EXPLANATION (i -]vr and w-F sd = (4) {__]vr sd and siewely (8) fESaS]u-F and vé sd (c) M-F Sd and crse sd and slt-clay (0) FEEe}y-F and CRSE sd ¢E) Prpr]cRSE and m-£ sd (F) a Text-figure 5.—Bottom-sediment facies map based on major clusters (A-F) of figure 4. The capital and lower case letters in the explanation in- dicate the dominant and subordinate grain size classes, respectively. A more detailed breakdown of sediment composition can be found in Hathaway (1971) ; see also Milliman (1972). Sample stations explained in figure 1. they represented and because of conditions of their preservation. No single dead shell was accepted as an occurrence unless the species occurred in other samples in the area. All corroded and blackened shells were ignored. Living specimens of all of the more common forms were found. A wealth of information on the samples used, other than that given in Table 1, can be found in Hathaway (1971). BIOFACIES ANALYSIS Introduction.—In this report, stations that are similar to each other on the basis of the kinds and abundance of ostracodes present are delineated using the well-known correlation coefficient (r) as a similarity measure and prinicpal coordinates analysis (Gower, 1966; Blackith and Reyment, 1971). 474 J. E. Hazer Text-figure 6.— Principal coordinates analysis of 30 samples containing 126 species from the Cape Hatteras area. Eigenvalues and eigenvectors were extracted from a correlation matrix. Projections on the first three coordinate axes are shown. The first three axes account for 51 percent of the variation. No patterns that could be related to biogeography were evident in projections on six other axes. The dashed lines connect each sample to the sample with which it has the highest computed similarity. The three clusters of stations resulting from projections on the first two axes are considered to represent biofacies. Biofacies A and B represent the northern most part of the Carolinian Province and C the southernmost part of the Virginian Province. The biofacies are mapped in Text-figure 7. Second Coordinate Axis (II percent) Biofacies C t—+- First Coordinat: ta Bi a a meee Ae Yh Second Coordinate Axis (\l percent) +5 Biofacies B +4 +3 Biofacies C Biofacies A =i 0 First Coordinate Axis (29 percent) ani S2 +4 0/859 1860 1869 ©1440 a 1434@ 23210 1433@@ 2324 ae 2319@ 4 + 1436@ 2064 1438 2 1440 144] 1442 Fuss vss 1861 +4 : 1859 14390 1860 232 +3 2319 au 1435 e O13 +42 : t ioctl fat 1858 ae) e 2064@101871 1866 O ae sata. 4 |G +7 Third Coordinate Axis (8 percent) Fon jeneelin eC s00 70 PUEN OS 2 USemMzeq Si enjien pozeynoj}eo oyz Sueew cd°s F “St PEUX) SSE}9 TULOd=-9 5672 © ULYJIM S}]}]e} UaALB onjeA BYR ZeEYY SAZedLpUL F SY *(896L) PUNTHIIM pue puojy]emM 50 sdew ay} wou} pazej}no)]e9 auam pue SYyzZUOW YSawWueM puke 3S9P}09 ayy JO} SAauN}eYaduazy wWo}OQ aBbeyuane aue saunzeuvadwa} uvawwns pue svazULM AY, “e}eP auNzPeuvadwazy pue “syydap suoltzeI07 -"L 919F1 0 Gc 6 G2°92 62" gL 72 SZ Le Se See2 4S¥ St 6L g2°S Ge 92 G2 be St Le 2 92 S¢ 722 1sy 9 2 20°S G2°92 G2°EL 9L 82 S2 9L S¢ E2e2 38V 72 2S 72°S 62°92 00°SL 9b 62 Sd 20 Ss zzez 3S i 6L2 of Y Sige Ge CO"SL 9L gS eo) 60 cs L262 38¥ 7 Se. ? S2°9e s2"9l 9L 84 G2 80 S¢ Oze2 3SV 82 S6L Seay) Sea S291 Zab 2S G2 £0 St 6lLe2 48V 0 S() 74S Ge Ve G2 OL 9L 90 92 9S Wee BlLe2 4SV 0 2o.7 Os*ze Se°9l 9L €2 92 £4 7¢ 2bE2 3SV 0 be"e S2°9e A 9L 92 92 Ze 7S 9L¢2 3S¥ 8 GL 02°S Sith SB OS 2 S2 O¢ G2 OS Ge S902 S99 LL OL 90,7 Seabe G2°8 Se 0¢ Giz 00 9% 7902 $°9 2S £L9 £0°2 G2°8L Ge°bLb Sy 8S vir 60 9S VL8b ses S7 Gee els] Sie S2°8L OO"CL Ton 00 Se 00 ae ¢28b Soo 7S. 6L2 Vomec G2°S8L G2°8 947 00 SZ 0S Ge c2Z8bL so9 SL Ze G25. Ge bd Se a (3/ 20 G2 L7 Se L28L soo 82 2S6 Oud G2°le G2° eb ay) 8S vite 62 Ge O28L SOD L8 968 68°2 Ge” Le Os"el C2 6S 72 L2 G¢ 698L SOO L2 622 192 OS 22 G2° Sb S8 SL G2 £0 Se 998L Sod 0s 26 TON SG Pe G2 EL 98 Le G2 LS 7 S98L Sod S9 S8slb Sc = G2 9d OO*SL LY SY Sf O77 b L98L Sod 7 BSL 88r2 00°S2 S2°eb 99 77 G2 zs 7E O098L SO5 Le e272 Boe G Se. 92 G2° 8b ge LO 92 07 7 6S8L sod 09 208 OFZ Sere OS*2L 9S 00 oF 62 7¢ 8S8L sod 9 2O¢ vee S2° 92 G2°8L 2£ 2b we O¢ 7¢ cyyL so9 Sf 682 LY 2 ae. Fe S2°8L Ld SL 92 Ov vas 277L Sso9 L2 78 OL°? OS." Z2 Se Gt SL VL 92 LS 7 L777 seg 82 ve2 £6°2 ie Se" 9L 82 00 92 0S vf O77L So9 aL 04 60°% Se 92 se -9t 02 00 92 8S eo 6e7L Sod 9L ce cee S292 S2°9L 22 vy G2 9S ve 8evL Sod 62 S6 iy aa 3 G2 792 $2 Ek 79 Le G2 6S VE 2¢9l 368 22 Leb 6C"E « 00°S2 G2°eb 92 L2 G2 20 Se 9e7L SOD Zl ES 6L°¢ G2" Ee G2°eb 22 Sl G2 LL S¢ SfcvL Se5 LS S7¢ os. 9 00°S2 Os"2L S2 SL G2 02 Se 7o7L SOD Ee 97S Le"? 00°S2 S2° bb O¢ Sl G2 Le s¢ eev_ soo ee L22 8L°Y S2°L2 ¢2°8 vas SL G2 Ov Se 2e7b Soo 27 761 i a Sele g2"9 2¢ Sl G2 LS se LevbL Soo 22 2b oa s G2°SLt G2°St Se 9 S2 00 ce Of7L Sod s Jo Jo ‘utw ‘bap ‘utcw =" Bap a)dwes SalLoadg suaw *“qejsu] “dwat *dwat (Sua jaw) 759m yzuou -t9eds "awe JawWns JazULM yzdeg apny.i.bu07 apnzize) -uoLjze3S yoea ye SyqzUOW Z|, so}, SaBevere @4N}e4edWay WOIOG AYA BULSN pazejND]e9 SUOLZELABP puepueZs GYR Bue AQL]IGeRSUL auNZevadway JO}F SON}EA BYL *( CCOCL pue oCS*Z UBAMZEq St ON}eA paze}Nd}e9 ayy SueeW Gs*g F “St FOUF) sse@)92 JU$0d-9.6°2 © ULY3IM $1104 U@ALB onj,eA O43 2eY4X SOIED!pUL F BYR $(896L) PUNIHIEM PUB P4OF)eM ag SdeW 84 WOU POZE1NDZ1/€9 e4eM pue SYZUOW YSeWUeM PUe YSOP}OD YF 4OF seunjzevedwe, woz20q ebed O48 SO4UNIC4EdWe% VoWwWNS PpUue Ye{QUEM eYL *e20eP eUNIeVedWwe pues ‘yadep *uop3e@907 ="b e1qdeL Care HatrerAs OstTrAcopvE BIOFACIES 475 The resulting major clusters of stations are considered to represent biofacies and can be indicated on a map. The biofacies are thus delineated in Q-mode and are mappable and meaningful if they form recognizable patterns. A species-versus-species comparison (R-mode cluster analysis) is used to indi- cate which individual species are closely associated with each other and help explain the patterns seen in Q-mode. The species composing the clusters formed in R-mode have no fixed geographic position, and the clusters them- selves therefore have no a priori potential for mappability. The approach to the delineation of bioassociational units is that of Buzas (1970, p. 113), Hazel (1970b), and others. In contrast to this is the methodology advocated by Kaesler (1966, 1969) in which biofacies are clusters formed in R-mode, and Q-mode clusters are referred to as biotopes. This is considered unsatisfactory herein, largely because I believe that biofacies should be map- pable no matter how they are delineated, just as are bottom-sediment facies and lithofacies. A more flexible definition of the term biofacies than R-mode clusters is believed desirable. One application of this would be to Q-mode bioassociational groupings (Mello and Buzas, 1968, p. 749). A biotope is a physical and biological system of which a fauna and/or flora is a part; the biotope is not the fauna or flora itself and, therefore, cannot be defined directly by the comparison of samples composed only of biotic constituents. Biofacies delineation.— From the 34 samples containing ostracodes, 126 species have been identified (Table 2) and 8894 specimens counted. Four samples were barren. Four contain very few specimens and were not used in the multivariate analyses. The remaining 30 samples were compared in Q-mode using principal coordinates analysis; figure 6 contains the results of ordination. In Text-figure 6, three major clusters of stations result from projections on the first two coordinate axes which account for 40 percent of the variation. On the first coordinate axis, northern stations have high negative values and southern stations, high positive values. Stations from the immediate area of Cape Hatteras have intermediate values but overlap strongly with those to the south. The major biogeographic pattern in the area is outlined on this axis. On the second axis, the immediate cape area stations are delimited from those to the south. Little biogeographic information appears to be contained on the third or other axes. The three groupings of stations on the first two axes are considered to represent biofacies, designated A, B, and C. The map distribution of these units is indicated in Text-figure 7. 476 ick s Hazes Table 2.— Alphabetical listing of ostracode species found in Cape Hat- teras area samples. The 76 more common species are indicated by numbers in parentheses following their names. These numbers are the code designation for the taxa in the R-mode dendrogram in figure 8; their occurrence and abundance can be found in figure 8. The occurrences of the rarer species are indicated in this table by the four-digit numbers following the species names; these numbers correspond to the sample numbers of table 1. Many of the species in the list below have been recently illustrated by Valentine (1971). References, other than those containing the original descrip- tions, in which some of the above species have been illustrated, include Plusquellec and Sandberg (1969), Hazel (1967), Hulings (1966, 1967), Benda and Puri (1962), Engel and Swain (1967), Benson and Coleman (1963), Swain (1968), Puri (1958a,b), Hall (1965), Williams (1966), and Grossman (1967). That there has been relatively little work on American east coast Quaternary ostracodes is illustrated by the fact that about one half of the species delineated have not been formally proposed. Actinocythereis dawsoni (Brady, 1870). (1) A ; sp. B. (2) Argilloecia sp. A. 1423, 1874 Al sp. B. 1863 A. sp. C. 1860 Aurila laevicula (Edwards, 1944). 1442, 1858, 1861, 2321, 2322 Basslerites miocenicus (Howe, 1935). 1869, 2321 BE sp. A. 1869 B. sp. B. 1858 Bensonocythere americana Hazel, 1967. (9) arenicola (Cushman, 1906). (10) whitei (Swain, 1951). (12 sapeloensis (Hall, 1865). 1869, 1870, 2322 sp. K. 1434, 1859 sp. M. (16) sp. U. 1431 spe CG; (14) sp. EE. (13) sp. FF. (15) Bythocythere sp. A. (18) B. sp. B. (19) Campylocythere laeva Edwards, 1944. (20) Caudites nipeensis Bold, 1946. 1860 Cushmanidea seminuda (Cushman, 1906). (22) Po Bo Ba) Palboliee Ee eae S G: cf. C. seminuda. 1866 Cytherella sp. A. 1869 Cytherelloidea a A. 1443 Cytherois . A. 1861 Cytheromorpha picai ap aa Williams, 1966. (28) Cytheropteron pyramidale Brady, 1868. (29) (On eee Puri, 1954. 1859 GC: 5 Jae IEKGIL, 1869 G- - D. 1869 Cytherura elongata Edwards, 1944. (32) forulata Edwards, 1944. (33) howei (Puri, 1954). (34) pseudostriata Hulings, 1966. (35) wardensis Howe and Brown, 1935. (37) sp. A. (38) sp. B. (39) Sele tele Sel Care HatreraAs OsTRACODE BIOFACIES sp. C. 1431, 1434 sp. D. 1430, 1431, 1861, 1869 sp. E. 1869, 1870, 1874 2 He) (43) sp. G. (44) sp. H. 1869 sp. J. 1434, 1870 spr Le. (36) chinocythereis margaritifera (Brady, 1868). (47) planibasalis procteri (Blake, 1929). (48) sp. A. (49) ucythere declivis (Norman, 1865). (50) gibba Edwards, 1944. (51) triangulata Puri, 1954. 1861, 1869 sp. A. 1865, 1870 Rismarchinella finmarchicd (Sars, 1865). (54) “Haplocytheridea” bradyi (Stephenson, 1938). (55) Hulingsina americana (Cushman, 1906). (60) glabra (Hall, 1965). (58) rugipustulosa (Edwards, 1944). (59) Spe (57)) sp. E. (61) sp. F. (62) sp. I. (63) Nancsia cf. J. acuminata (Sars, 1865). 1863, 1869, 1870 Krithe sp. A. 1869 Leptocythere angusta Blake, 1929. (66) Loxoconcha matagordensis Swain, 1955. 1861 See Be ee els ae 2 S SEER mB BB SB ike reticularis Edwards, 1944. (70) Ibe Sperata Williams, 1966 (71) Te sp. C- ee The sp. He (67) Loxocorniculum postdorsolatum (Puri, 1960). 1434, 1869 Macrocyprina sp. A. 1860, 1863 M. sp. B. 1869 Macrocypris sp. E. 1869 Microcytherura choctawhatcheensis (Puri, 1954). (76) M. sp: AN (77) M. sp. B. 1432 M. sp. C. 1870, 2321 M. sp. D. 1430 Muellerina canadensis (Brady, 1870). (80) M. lienenklausi (Ulrich and Bassler, 1904) s.l. (81) Munseyella atlantica Hazel and Valentine, 1969. 1866 Neocaudites triplistriatus (Edwards, 1944). 1863 Neolophocythere subquadrata Grossman, 1967. (83) Orionina bradyi Bold, 1963. 1861 Paracytheridea altila Edwards, 1944, (86) Pe rugosa Edwards, 1944. (87) Vee Spy AG ((88) Paradoxostoma delicata Puri, 1954. (89) P: sp. A. 1861 P: sp. C. 1874 P. sp. D. 1860, 1861, 1870 477 478 jo: Hager Paranesidea sp. es (92) IES . D. 1860, 1869 Pellucistoma nenaene Edwards, 1944. (95) P. sp. A. (96) Phlyctocythere sp. A. (97) P: sp. B. 1861, 1869 Pontocypris sp. A. 1860, 1861 Pontocythere sclerochilus (Tressler and Smith, 1948). 1870 iP: sp. A. (23) P. sp. B. (24) 12% sp. C. 1434, 1870 Propontocypris aff. P. howei (Puri, 1954). (101) Proteoconcha gigantica (Edwards, 1944). (102) jee multipunctata (Edwards, 1944). 1439 1. nelsonensis (Grossman, 1967). (104) P. tuberculata (Puri, 1960). (105) Protocytheretta danaiana (Brady, 1869). (106) Ie montezuma (Brady, 1869). (107) Pseudocytheretta edwardsi Cushman, 1906. Hoe Pterygocytherets ad (Blake, 1929). (109) Pe sp. A. (110) Puriana faridaae ‘Puri, 1960. (111) IP. rugipunctata (Ulrich and Bassler, 1904). (112) BR. Sjoh Z\5 (tts) 124 sp. B. (114) Radimella? floridana floridana (Benson and Coleman, 1963). (3) “Sahnia”’ foveolata (Brady, 1870). (116) “gy sp. B. (117) eSee jo, (EZ (215) Sclerochilus sp. A. 1870 S. sp. B. 1874 Xiphichilus sp. A. 1866 The dashed lines in the upper left plot of Text-figure 6 connect eack sample to the one with which it has the highest computed similarity. The only three samples that do not link with any of the samples in their respective clusters are 1858 and 1866 of biofacies B and C, respectively, which have the highest resemblance to each other and 2321 of biofacies A which has its greatest similarity with 1438 of biofacies B. The relationship between 1858 and 1866 is expressed on the third coordinate axis and is caused by the mutual abun- dance of Echinocythereis margaritifera (Brady, 1868) (Text-fig. 8). However, in terms of the rest of the assemblage, 1858 and 1866 are consistent with the samples with which they are grouped on the first two axes. Sample 2321 has a slightly higher average similarity with the other samples placed in biofacies A than it does with those of biofacies B. On the right in Text-figure 8, the samples of this study are grouped by biofacies. At the bottom in this figure is an R-mode dendrogram for virtually all of the 76 species that were found in more than two of the 30 samples used in the multivariate analyses. Opposite the endpoints of the dendrogram the occurrences of the species are plotted against the samples. Their relative abundance is indicated by symbols representing point classes of percent contri- bution on a geometric scale (except for the smaller samples for which an oc- Carr HatrerAs OstTrACODE BIOFACIES 479 currence is indicated by an X). The figure thus serves as an occurrence chart and also as a base for interpreting the Q- and R-mode clusters. Of the species that occur in biofaces A, relatively few are the principal contributors to the samples with significant numbers of specimens. The domi- nant elements (in terms of their relative abundance) are Hulingsina americana (Cushman, 1906), Puriana floridana Puri, 1960, and Hulingsina sp. E from the R-1 cluster of figure 8; “Haplocytheridea” bradyi (Stephenson, 1938) from the R-2 cluster; Protocytheretta montezuma (Brady, 1869), cluster R-3; and Cytherura sp. A, Proteoconcha gigantica (Edwards, 1944), Hulingsina rugi- pustulosa (Edwards, 1944), and Paradoxostoma delicata Puri, 1954, from clust- ers R-5 and R-6. Note that no species are restricted to this biofacies. Biofacies Text-figure 7.— Map distribution of the biofacies delineated by principal coordinate analysis (Text-fig. 6). Biofaces A and B are considered to repre- sent the northern part of the Carolinian faunal province and biofacies C, the pens part of the Virginian Province. Sample station explained in Text- igure 1. 480 J; ES Hazer Text-figure 8.— Occurrence, abundance, and associations of 76 ostracode species occurring in three or more samples. The R-mode dendrogram is based on a correlation matrix and clustered by the unweighted pair-group method. Code numbers are keyed to species listed alphabetically in Table 2. On the right in the figure the samples are grouped by biofacies. In the body of the figure the percent abundance of the species is indicated by symbols for all samples, except for those in which the numbers of specimens found were too few to make the percentages meaningful. Occurrences for species in latter group of samples are indicated by an X. SIMILARITY COEFFICIENT (r) Biofacies C — — Biofacies B Biofacies A LL - 60 -80 -100 -40 60 40 20 80 a call ee eee Pee oa 91 ‘i =e * 8 « . (a6 OD) LO fss a . = €9 |° @OO0O0.-.. ae «Ox a 1a) 8) Vi Cite ee eo) 6 een ry ' = Bc |S OF 3 Oo os | one ; OT - walta t ZIL]® OO OCBe#OOOO © » 911 -@0 y = =] 18 |® * ©COOOOO 1 62 Cia © ® [o) og EL, |. © ©8-6 ML \\* hac - @ P 81 kt te F 6 . ©- (Om DOM Z 08 |- ss Ts OROL@, © Shei hic -OO08-®@ ein lle c POON TOL ©80+ O08 8@@leQ . 80L]- S98 @GO0OO8B@O|- . = Me O©OGBBGOO90 a eg |° ae a © Qh v ous 4 ey 49 |Ox@o- (OM OMOMO} TO) . I © . wo raliee te BE (ORR OMOM OMEONO) ©- SO) . Ze |O© © ®9+-+O080 Ole O©+ + @88® . Ez? oes Oia. Je ; © 6£ . . . a SIlji- O98 ©+®8 ©|@ ~ LG |*X++@0@--6 ; ° ZT ]}* @©@-@0000| .. oa OS . - @ ©. (0) e ware 89 *@0000 . : 9S : ©-e@- ie 7€ 7 + @- an 68 |. . ° "a -|© ‘ - me 6S @--. . -1@- 2 aus a) col . © - | 8s 10 @ @ -1®®+-@00 +--+ xxx BO; |= @- sins a L6 e ° s = “a 88 Fee + 601}° . © Ly |© «ies ae LOT]2 @:- aE OC) ee - @ = 90IIOX OVBHOGOH@Ol®-+-++-O0--@ bo 47 Go Giorees Miele. © . rd ‘1 * 216 © e Sol ° ONO - -5¢ |> @- a: ©©200800 = Lg |° oe ar O) COMO) 76 . . - = ® Hh |° . . . ®e- 66 |© ° oe OM OM oA 9¢ |o ‘ -|0080 ©8 Go 79] x sss OG @@00-- IS a . E ‘ c7 |* -|©® - F =e © 8, 8 8: 4g —— OC 1s : . cs - i ers ° E OLTe ee -1-@@O°-s © ee ee SS A -+ +1 @O0+ O- as Oo 2 2 = o X@>--> . Coa ©8X GOOO ee fy tee Re ell ; : as * wu w a -~{ 5 ae “oe ee OM KW 6” |° “2 oil aa. @ Qe = a oe 2 Il ©8O808-. c 98 |: . ®20:08 oO 8S |- “ = . ILl]- er teh . . ©GGeO®- 09 |@xXxG©GCOOOORS O}FROCCCCCCE OL |* X ° . ®-| ®@8® +90 e OL : 4d pe uavke 61 -| @O + © ZE . . s&s *-@++OQ® LEE 1® OGB8OBO+s @®S/OOe#OOOS8D £ |® ts) ° + @O/OOOKGSSOO SSSSSESSSSERSERRERSESSS ool- o8- 09- On- Oz- i) 0z 0” 09 08 FOL, SSNS OSE OGIO EP er Ses : | (4) LNAIOI4AdOO ALIUVTINIS > sopoezord aq sarorjord Carre HatreraAs OsTRACODE BIOFACIES 481 A has a map distribution in the Cape Hatteras area very similar to biofacies 3 of Valentine (1971) and Hazel (1971), which was defined using binary data and the Dice coefficient. Most of the rest of the area south of Cape Hatteras is inhabited by the assemblages of biofacies B, which is characterized by high density and diversity; the dominant species appear in the R-1 through R-6 clusters of figure 8. The consistently occurring abundant species of biofacies B include Cytherura forulata Edwards, 1944, Hulingsina americana (Cushman, 1906), Radimella? floridana floridana (Benson and Coleman, 1963), Puriana flori- dana Puri, 1960, Hulingsina sp. E, Cytherura sp. L, Pellucistoma magniventra Edwards, 1944, and Cytherura sp. A. Several other species are consistent in their occurrence but are not as abundant. Biofacies A and B I believe represent biogeographic units within the subtropical Carolinian Province. The assemblage composition of biofacies C is manifested in the large R-mode cluster of Text-figure 8 containing the labeled clusters R-7 through R-11. Note that relatively few of these species occur in biofacies A and even fewer in biofacies B. It is also evident that more cryophilic than thermo- philic species are terminating their equatorward or poleward expansion in the Cape Hatteras area. The dominant elements of biofacies C include Puriana rugipunctata (UI- rich and Bassler, 1904), Muellerina lienenklausi (Ulrich and Bassler, 1904), Bensonocythere whitei (Swain, 1951), B. arenicola (Cushman, 1906), Cytherura wardensis Howe and Brown, 1935, Microcytherura sp. A, Loxoconcha sp. H, Loxoconcha sperata Williams, 1966, Pseudocytheretta edwardsi Cushman, 1906, Propontocypris aff. P. howei Puri, 1954, Leptocythere angusta Blake, 1933, Hulingsina sp. I, Protocytheretta danaiana (Brady, 1869), Hulingsina ameri- cana (Cushman, 1906), Cytherura forulata Edwards, 1944, and others. Discussion. — The use of species counts and a multistate quantitative similarity measure and principal coordinates analysis allows the clear delineation of the major ostracode biogeographic patterns in the Cape Hatteras area. In gross form, the three major biogeographic units delineated, biofacies A, B, and C, are very similar to those described for the area by Valentine (1971) and Hazel (1971), using most of the same samples and a binary (presence-absence) coefficient and cluster analysis. Therefore, if the most general structure is all that is desired, presence-absence data may be all that is necessary. This conclusion was also reached by Buzas (1972) in a study of foraminifer distri- butions. The results with binary and multistate data in this area are similar partly because the area is the biogeographic endpoint for many cryophilic and thermophilic species. However, if the change in assemblages is manifested mainly by changing numerical dominance of species, this would be obscured by the use of binary data. Also, with ostracodes at least, once the organisms have been sorted for identification, they can be counted rather quickly. There- fore, in the modern environment where contemporaneity is assured (in contrast 482 J. E. Hazex to paleobiogeography where larger units of time must be used), it is recom- mended that counts and multistate measures and classification systems be used to obtain the most information. RELATIONSHIP OF BIOFACIES TO MACROENVIRONMENTAL FACTORS General. — The 38 samples used in the present study lie in a 10,000-km? area. Therefore, they are quite inadequate for any aut- or synecological analysis. The data bank, however, I believe to be adequate for biogeographic purposes, and the biofacies delineated to be valid. In an open marine shelf environment, many abiotic factors such as salinity and available oxygen can be effectively eliminated as being of primary influence in controlling the faunal composition of biofacies. The podocopid ostracodes are part of the microscopic wandering benthos and, for the most part, scavenge for food on the bottom or just below the sediment-water interface, or live on marine plants. If an adequate food supply is available, temperature and bottom-sediment size are commonly believed to be two primary factors controlling the distribution of species. One of the objects of this study was to see if the delineated biofacies composition could be shown to be largely controlled by either or both. Temperature should have a more direct relationship to species distribu- tion than other abiotic or biotic factors simply because, particularly for benthic species without planktonic larvae, the statement can be made that a species cannot live at a particular place if its thermal] survival limits are exceeded or if temperatures needed for reproduction are not met (Hutchins, 1947; see Hazel, 1970a, for discussion as applied to ostracodes). Temperature exerts controls on species distribution before other abiotic and density-depen- dent factors become influential. Thus, even when it is understood that there is in a species both individual and deme adaption, and therefore variation with respect to tolerance of thermal] fluctuation, temperature would tend to have a presence-absence effect. In contrast, such factors as available food, suitable substrate, and available light, are themselves generally gradational, and the effect on organisms of any of these factors would be manifested as changes in abundance. Biofacies and bottom-sediment facies. —Text-figure 4, as discussed above, is a dendrogram based on grain-size data for the 38 stations in this study; Text-figure 5 indicates the map distribution of the bottom-sediment facies thus defined. A comparison of the biofacies map (Text-fig. 7) with the bottom-sediment facies map shows that there is no obvious correlation of par- ticular biofacies with particular sediment facies. Thus, the type of substrate in this instance would seem to have minimal effect on the distribution of biofacies. Biofacies and temperature.— A comparison of the isothermal map for the warmest month (Text-fig. 3) and the biofacies map (Text-fig. 7) sug- Care HatTTerRAs OsTRACODE BIOFACIES 483 gests that summer temperature is the most important factor controlling the major faunal pattern seen, that is, the two major sample groupings on the first coordinate axis of Text-figure 6, which delineates the northern from the two southern biofacies in the area. The boundary between these major biofacies is near the 22.5°C and 25°C isotherms. All the stations assigned to biofacies C are on the cool side of the 25°C isotherm. That summer tempera- tures are the most important is graphically indicated in Text-figure 8. Note that many of the species of the R-1 through R-6 clusters, which contain the principal elements of biofacies A and B, also are found in biofacies C. In other words, many thermophilic species which are expanding their range from the south pass Cape Hatteras. In contrast, many of the species of the other major R-mode cluster, which contains the principal elements of biofacies C, are not found or are very rare at stations assigned to biofacies B and, to a lesser extent, biofacies A. Note that most of the biofacies A occurrences of cryophilic species are at stations 1434 and 1436 and that the calculated position of the 25°C isotherm is at these stations also. More cryophilic species, expanding their range from the north, terminate at Cape Hatteras than do thermophilic species; the warm bottom temperature in the cape area acts as an effective barrier to migration of northern forms. In contrast, the summer maximum in most of the area of both biofacies A and B is between 25.0 and 27.5°C; thus summer temperature would seem not to be an important factor here. No clear-cut correlation is suggested by the map of winter isotherms either. Further, as mentioned above, biofacies A is similar in its map distribution to a biofacies defined on binary data by Valentine (1971) and Hazel (1971); that biofacies has a discontinuous distri- bution, occurring in nearshore Raleigh, Onslow, and Long Bays, particularly near inlets, and on Diamond, Cape Lookout, and Frying Pan Shoals. The composition of biofacies A appears to be related to physical characteristics associated with the shoals and inner parts of the bays. Tolerance to instability of substrate in the form of both turbidity and turbulence is probably most important. REFERENCGES Arx, W. S. von 1962. An introduction to physical oceanography, Reading, Mass., Addi- son-Wesley, 422 pp. Benda, W. K., and Puri, H. S. 1962. The distribution of Foraminifera and Ostracoda off the Gulf Coast of the Cape Romano area, Florida. Gulf Coast Assoc. Geol. Soc., Trans., vol. 12, pp. 303-341. Benson, R. H., and Coleman, G. L., Il 1963. Recent marine ostracodes from the castern Gulf of Mexico. Kan- sas Univ., Paleont. Contr., 31, Arthropoda, art. 2, 52 pp. Blackith, R. E., and Reyment, R. A. 1971. Multivariate morphometrics. London, Academic Press, 412 pp. Blanton, Jackson 1971. Exchange of Gulf Stream water with North Carolina shelf water in Onslow Bay during stratified conditions. Deep-Sea Research, vol. 18, No. 2, pp. 167-178. 484 IEE. Hazer Bumpus, D. F. 1955. The circulation over the continental shelf south of Cape Hatteras. Amer. Geophys. Union, Trans. vol. 36, pp. 601-611. Bumpus, D. F., and Lauzier, L. M. 1965. Surface circulation on the continental shelf off Eastern North America between Newfoundland and Florida. Amer. Geog. Soc., Serial Atlas Marine Environment, Felio 7. Buzas, M. A. 1970. On the quantification of biofacies. North American Paleont. Con- vention, Chicago, 1969 Proc., Pt. B, pp. 101-116. 1972. Biofacies analysis of presence or absence data through canonical variate analysis. Jour. Paleont., vol. 46, No. 1, pp. 55-57. Cerame-Vivas, M. J., and Gray, I. E. 1966. The distributional pattern of benthic invertebrates of the con- tinental shelf off North Carolina. Ecology, vol. 47, No. 2, pp. 260- 270. Dana, J. D. 1853a. Crustacea. U.S. Exploring Expedition [Report], 1838-1842, vol. 14, pt. 2, pp. 690-1618. 1853b. On an isothermal oceanic chart, illustrating the geographical distribution of marine animals. Amer. Jour. Sci., ser. 2, vol. 16, pp: 153-167, 314-327. Day, J. H., Field, J. G., and Montgomery, M. P. 1971. The use of numerical methods to determine the distribution of the benthic fauna across the continental shelf of North Carolina. Jour. Animal Ecology, vol. 40, pp. 93-125. Defant, Albert 1961. Physical oceanography, volume 1, New York, Pergamon Press, 729" pp: Engel, P. L., and Swain, F. M. 1967. Environmental relationships of Recent Ostracoda in Mesquite, Aransas and Copano Bays, Texas Gulf Coast. Gulf Coast Assoc. Geol. Soc., Trans., vol. 17, pp. 408-427. Gower, J. C. 1966. Some distance properties of latent root and vector methods used in multivariate analysis. Biometrika, vol. 53, No. 3/4, pp. 325-338. Grossman, Stuart 1967. Ecology of Rhizopoda and Ostracoda of southern Pamlico Sound region, North Carolina; Part 1, Living and subfossil rhizopod and ostracode populations. Kansas Univ., Paleont. Contr., 44, Ecology, art. 1, pp. 1-82. Hall, C. A. 1964. Shallow-water marine climates and molluscan provinces. Ecology, vol. 45, No. 2, pp. 226-234. Hall, D. D. 1965. Paleoecology and taxonomy of fossil Ostracoda in the vicinity of Sapelo Island, Georgia, Report 4, Kesling, R. V., and others, Four reports of ostracod investigations. Ann Arbor, Univ. Michi- gan Press, pp. 1-85. Hathaway, J. E. 1971. Data file continental margin program Atlantic Coast of the United States; vol. 2, Sample collection and analytical data. Woods Hole Oceanographic Institution, Ref. No. 71-15. Hazel, J. E. 1967. Classification and distribution of the Recent Hemicytheridae and Trachyleberididae (Ostracoda) off northeastern North America. U.S. Geol. Sur., Prof. Paper 564, 49 pp. Caper HatreraAs OsTRACODE BIOFACIES 485 1970a. Atlantic continental shelf and slope of the United States — Ostra- code zoogeography in the southern Nova Scotian and northern Virginian faunal provinces. U.S. Geol. Sur., Prof. Paper 529-E, 21 pp. 1970b. Binary coefficients and clustering in biostratigraphy. Geol. Soc. America, Bull., vol. 81, No. 11, pp. 3237-3252. 1971. Paleoclimatology of the Yorktown Formation (upper Miocene and lower Pliocene) of Virginia and North Carolina. In Oertli, H. J. (ed.), Paleoecologie ostracodes. Centre Rech., Pau, Bull. 5 supp. 1, pp. 361-375. Hulings, N. C. 1966. Marine Ostracoda from the western North Atlantic Ocean off the Virginia Coast. Chesapeake Sci., vol. 7, No. 1, pp. 40-56. 1967. Marine Ostracoda from the western North Atlantic Ocean between Cape Hatteras, North Carolina and Jupiter Inlet, Florida. Bull. Marine Sci., vol. 17, No. 3, pp. 629-659. Hutchins, L. W. 1947. The bases for temperature zonation in geographical distribution, Ecological Monographs, vol. 17, pp. 325-335. Johnson, C. W. 1934. List of marine Mollusca of the Atlantic Coast from Labrador to Texas. Boston Soc. Nat. Hist., Proc., vol. 40, No. 1, pp. 1-204. Kaesler, R. L. 1966. Quantitative re-evaluation of ecology and distribution of Recent Foraminifera and Ostracoda of Todos Santos Bay, Baja Cali- fornia, Mexico. Kansas Univ., Paleont. Contr., 10, 50 pp. 1969. Aspects of quantitative distributional paleoecology. In Merriam, D. F. (ed.) Computer applications in the earth sciences. New York Plenum Press, pp. 99-120. Maturo, F. J. S. 1968. The distributional pattern of the Bryozoa of the east coast of the United States exclusive of New England. Soc. Italiana Sci. Nat. e Museo, Atti vol. 108, pp. 261-284. Mello, J. F., and Buzas, M. A. 1968. An application of cluster analysis as a method of determining biofacies. Jour. Paleont., vol. 42, No. 3, pp. 747-758. Milliman, J. D. 1972. Atlantic Continental Shelf and slope of the United States — petrology of the sand fraction of sediments, northern New Jersey to southern Florida, U.S. Geol. Sur. Prof. Paper 529-J, 40 pp. Milliman, J. D., Pilkey, O. H., and Blackwelder, B. W. 1968. Carbonate sedimentation on the continental shelf, Cape Hatteras to Cape Romain. Southeastern Geology, vol. 9, pp. 245-267. Milliman, J. D., Pilkey, O. H., and Ross, D. A. 1972. Sediments of the continental margin off the eastern United States. Geol. Soc. America, Bull., vol. 83, No. 5, pp. 1315-1334. Plusquellec, P. L., and Sandberg, P. A. 1969. Some gencra of the ostracode subfamily Campylocytherinac. Micro~ paleontology, vol. 15, No. 4, pp. 427-280. A In ES 1958a. Ostracode Subfamily Cytherettinae. Gulf Coast Assoc. Geol. Soc.,. Trans., vol. 8, pp. 183-195. 1958b. Ostracode genus Cushmanidea. Gulf Coast Assoc. Geol. Soc., Trans., vol. 8, pp. 171-181. 486 ES HaAzee Sandberg, P. A. : 1969. Appendages and family placement of the ostracod genus Pelluct- stoma. Jour. Paleont., vol. 43, No. 5, pp. 1174-1178. Schnitker, Detmar 1971. Distribution of Foraminifera on the North Carolina continental shelf. Tulane Studies Geol. Paleont., vol. 8, No. 4, pp. 169-215. Schroeder, E. H. ; 1966. Average surface temperatures of the western North Atlantic. Bull. Marine Sci., vol. 16, No. 2, pp. 302-323. Stefansson, Unnstfeinn, and Atkinson, L. P. 1967. Physical and chemical properties of the shelf and slope waters off North Carolina. Duke Univ. Tech. Rept., 230 pp. Stefansson, Unnsteinn, Atkinson, L. P., and Bumpus, D. F. 1971. Hydrographic properties and circulation of the North Carolina shelf and slope waters. Deep-Sea Research, vol. 18, No. 4, pp. 383- 420. Stephenson, T. A., and Stephenson, Anne 1954. Life between tide-marks in North America — [Parts] IIIA, B, Nova Scotia and Prince Edward Island. Jour. Ecology, vol. 42, No. 1, pp. 14-45, 46-70. Swain, F. M. 1968. Ostracoda from the Upper Tertiary Waccamaw Formation of North Carolina and South Carolina. U.S. Geol. Sur., Prof. Paper 573-D, 37 pp. U.S. Army Corps of Engineers 1964. Outer banks between Ocracoke Inlet and Beaufort Inlet, North Carolina. U.S. Army Corps Engineers, Combined Rept., U.S. Army Engineer District, Wilmington, North Carolina, 26 pp., Appendices A-H. U.S. Congress 1948. North Carolina shore line, beach erosion study. House of Repre- sentatives, U.S. Congress, 80th, 2d sess., House Doc. 763, 33 pp. Valentine, P. C. 1971. Climatic implication of a late Pleistocene ostracode assemblage from southeastern Virginia. U.S. Geol. Sur., Prof. Paper 683-D, 28 pp. Walford, L. A., and Wicklund, R. I. 1968. Monthly sea temperature structure from the Florida Keys to Cape Cod. Amer. Geog. Soc., Serial Atlas Marine Environment, Folio 15. Wells, H. W., and Gray, I. E. 1960. The seasonal occurrence of Mytilis edulis on the Carolina coast as a result of transport around Cape Hatteras. Biol. Bull., vol. 119, pp. 550-559. Williams, R. B. 1966. Recent marine podocopid Ostracoda of Narragansett Bay, Rhode Island, Kansas Uniy., Paleont. Contr., 11, 36 pp. Joseph E. Hazel, U.S. Geological Survey, Washington, D.C. 20244 DISCUSSION Dr. R. A. Reyment: Several people have discussed quantitative studies during this meeting. One of the questions which has arisen is whether one should use factor analysis or not. I hope those who asked these questions were listening attentively to Dr. Hazel’s paper, because he gave an excellent discussion of what may be considered the optimal method, that is, that of principal co- Cape HaTTERAS OsTRACODE BIOFACIES 487 ordinates, proposed by J. C. Gower, for the problem which is frequently in- correctly or inaccurately treated by the factor analytical model of psychological or psychometrical work. Dr. Hartmann: What was the percentage of amphiatlantic species in the dif- ferent regions you studied? Dr. Hazel: Of the 136 sublittoral species I identified in the Cape Hatteras area only three are amphiatlantic. These are Finmarchinella finmarchica (Sars, 1865), Eucythere declivis (Norman, 1865), and Cytheropteron pyramidale Brady, 1868. Of the about 200 podocopid ostracode species living in open marine sublittoral waters from Nova Scotia to South Carolina, only 21 seem also to occur in Europe and all but six of these are restricted to north of Cape Cod. Thus, only about 4% of the species found south of Cape Cod, which is the southern limit of the cold-temperat Nova Scotian faunal province, are amphiatlantic. In the Nova Scotian Province, however, about 33% of the species also occur in the eastern Atlantic. The amphiatlantic species are of two basic types. Those such as Baffini- cythere emarginata (Sars, 1865), B. howei Hazel, 1967, and Finmarchinella barenzovoensis (Mandelstam, 1957) live in the frigid Arctic province and penetrate equatorward into cold-temperate or northern mild-temperate waters. In contrast, species such as Hemicythere villosa (Sars, 1865), Finmarchinella finmarchica (Sars, 1865), and Cythere lutea Mueller, 1785, occur only as far poleward as the subfrigid provinces. These forms probably became amphi- atlantically distributed during Pleistocene interglacial stages. hee 1h "ant pgs * Wren : i ined Mahe th note 4 res Beas mh) we ns ” o lah Papin aa ors yo hi iatte vis 4 eu “da 9} plage wr a | int Sy aefiah nrly nA { teat oft re it an to aye siK RULE, on" pi i sats Pyew,” ey : vid mrsiges ail at ge Sen ar) ! an ry “NY ¢ ha ra B deg 30 wi aie wiwathqarett fia Taine ' tale ges bad con) HM tab CRY S Jha duthe OA ; effiGs la stereqaiet ifr ntetl: thes orohat 7 | “3 7 . PAGES "bell “ CeOpe abr t “44 - ut cali he fowls i bheha Wwe le ; ob ton aint = i? : i f 7 ~ OSTRACODES OF THE MANGROVES OF SOUTH FLORIDA, THEIR ECOLOGY AND BIOLOGY DieTMarR KEYSER Zoologisches Institut und Museum, Hamburg ABSTRACT This is a preliminary report on the living ostracode population of the mangrove swamp area in South Florida. It deals mainly with the salinity range of some more abundant forms living in the oligo- and mesohaline region. The investigation shows that the border between the oligohaline and mesohaline at 4.5 o/oo salinity is distinct. It represents the upper limit for the freshwater-forms and the lower limit for nearly all of the halmyrobe species. Only two species have been found to cross this border: Cyprinotus sp. II and Cypridcis ? beaveni Tressler and Smith, 1948. A second limit might be the 10 o/oo salinity for some species accustomed to higher salinity. They are repre- sented in this study by Cytherura forulata Edwards, 1944, Reticulocythereis floridana Puri, 1960, and Reticulocythereis sp. II. Besides Cyprinotus, another true brackish-water group of Cypridacea, is reported. The Thalasso- cypridini appear with three species of the genus Parapontoparta only in the halmyrobe region. LES OSTRACODES DES MANGLIERS DU SUD DE LA FLORIDE LEUR ECOLOGIE ET LEUR BIOLOGIE RESUME La plupart des ostracodes de la cote du golfe ne sont connus que par leur carapaces. Toutes les études écologiques faites dans cette région sont basées sur des espéces déterminées par cette origine. Il n’y a aucun doute de ce que les études écologiques de ce genre sont parfois problématiques. Ce fut, donc, trés important de compléter notre connaissances des ostracodes de la cote du golfe par l’investigation de populations vivantes d’ostracodes a travers des méthodes zoologiques. L’auteur a échantillonné des ostracodes vivants pendant une période de deux années dans les marais a mangliers du sudouest de la Floride. Il était possible de receuillir un bon nombre de ces ostracodes connus uniquement par leurs carapaces jusqu’ici. Les descriptions exactes des portions mousses seront publiées plus tard. Une investigation écologique intensive (salinité, température, substratum, et cétéra) fut faite sur le champ. I] est donc possible de décrire l’écologie de la plupart des espéces receuillies et de comparer ces résultats avec des études antérieures. Le travail présente une description détaillée de l’écologie des ostracodes de manglier. Il montre clairement les résultats différents obtenus par des études faite faites avec des méthodes paléontologiques et zoologiques et les limites des études paléoecologiques. INTRODUCTION The ostracode fauna of the Gulf of Mexico has been described primarily in palaeontological papers. This means that the soft parts of most of the species of this region have not as yet been described. Secondly little is known about the ostracode fauna which inhabits the mangrove coasts in general. To solve both questions I have sampled the ostracodes of Southwest Florida, 490 D. Keyser where one of the largest mangrove swamps is located. A study is now under way to describe the soft parts and ecology of the forms collected there. This paper is a preliminary report of some more abundant forms living in the oligo- and mesohaline parts of the mangroves. It deals with material which has been collected by a handnet with a mesh width of 0.2 mm on a monthly base from August 20, 1969 to April 4, 1970. The ostracodes have been picked living under a stereomicroscope. Text-figure 1 shows the localities where the samples in this study were taken. The carapace morphology of most of the marine and brackish-water ostra- codes of South Florida has been figured by Puri (1960). The morphology of the fresh-water ostracodes is partly known by a paper by Furtos (1936). Puri and Benda (1962) published a paper on ecology in which they used mainly dead animals to characterize four biofacies. King and Kornicker (1970) in Texas established three biofacies by the use of living ostracodes. It seems that most of the workers are beginning to see that detailed ecologic data can only be gathered by the help of living specimen. Until recently an overall picture of the region in which one species lives was ac- cepted, but from this, one is only able to say which physical and chemical data he can correlate with the abundance, when he is comparing the population of living animals. MATERIAL I found 20 species in the oligo- and mesohaline region of Southwest Florida. I could identify 14 of them, mainly by means of the carapace morpho- logy. Seven of the species with five genera belong to the Cypridacea, while 13 species representing eight genera belong to the Cytheracea. These species are: CYPRIDACEA: Candona annae Meéhes, 1941 Cypretta bilicis Furtos, 1936 (? = C. braevisaepta Furtos, 1934) Cypria pseudocrenulata Furtos, 1936 Cyprinotus sp. II Parapontoparta sp. A Parapontoparta sp. B Parapontoparta sp. C CY DHERACEA: Limnocythere ?sanctipatricii Brady and Robertson, 1869 Cyprideis 2beaveni Tressler and Smith, 1948 Cyprideis salebrosa van den Bold, 1963 ?Haplocytheridea setipunctata (Brady, 1869) Perissocytheridea ?bicelliforma Swain, 1955 Perissocytheridea 2brachyforma Swain, 1955 Aurila conradi (Howe and McGuirt, 1935) Xestoleberis sp. A Cytherura elongata Edwards, 1944 Cytherura johnsoni Mincher, 1941 Cytherura forulata Edwards, 1944 Reticulocythereis floridana Puri, 1960 Reticulocythereis sp. Il JACKSONVILLE STATUTE MILES MAP OF SAMPLING AREA 492 D. Keyser ECOLOGICAL AND ZOOGEOGRAPHICAL DISTRIBUTION OF CYPRIDACEA Three species of the collected Cypridacea are already known from Florida (Furtos, 1936), but they were all reported from freshwater. I found Candona annae Méhes only in the limnic and oligohaline zone (Text-fig. 2), and this species obviously does not tolerate higher salinity waters. Its distribution includes Massachusetts, Florida, and Columbia, South America. Probably the limiting factor in Cypria pseudocrenulata Furtos and Cypretta bilicis Furtos (Text-fig. 2) is also salinity. These species are present in the oligohaline waters and two samples showed these forms in higher salinity water, but only in small numbers. Cypria pseudocrenulata has not been re- ported from brackish waters and neither has Cypretta bilicis. But C. pseudo- crenulata might be synonymous to Physocypria pustulosa Sharpe, which has been mentioned by Swain (1955) in Texas lagoons. Cyprinotus sp. II was present in oligo- and mesohaline conditions (Text- fig. 2). It probably tolerates higher salinity than the previous forms. This would be comparable to Cyfrinotus salinus Brady, 1862, which is known to live mainly in oligo- and mesohaline water and only seldom in fresh water (Klie, 1938). Another group of Cypridacea which was not encountered in fresh water is Parapontoparta sp. A, B, and C. To date they have not been reported from the Gulf Coast. The carapace shows some affinity to Aglaiocypris? figured by King and Kornicker (1970). Hartmann (1955) reported Parapontoparta from Brazil. Along with Cypfrinotus this is the second group of Cypridacea which are found in the brackish-water region of the Gulf Coast. Probably all ostracodes which belong to the Thalassocypridini are true brackish-water forms and are never found in the fresh water. All of the three species of Parapontoparta are swimming forms with a smooth translucent carapace. Parapontoparta sp. A (Text-fig. 2) is found on hard substrate covered by a small layer of soft or coarse detritus. The occur- rence of this form in the present study is limited to the entire mesohaline, ranging in salinity from 4.2 0/00 - 18.6 o/oo. Parapontoparta sp. B (Text-fig. 2) has a wider field of occurrence. I found it on silt, fine-medium sand and on mud. It seems that it does need some soft detritus, for I did not find it on sterile sand, silt or rock. The salinity range was from 4.2 0/00 - 20.9 o/oo. Parapontoparta sp. C (Text-fig. 2) did not occur as frequently as the other forms. It was the only Parapontoparta found in oligo-, meso- and polyhaline waters. Detritus was also present. The current affects these swimming forms more than burrowers, and I believe distribution of these animals is mainly influenced by currents. Para- pontoparta sp. B tolerates some current, for I found only one specimen on mud but 15 in a channel with a strong tide current. Soutuy FLtorma MANGROVE OsTRACODES 493 ECOLOGICAL AND ZOOGEOGRAPHICAL DISTRIBUTION OF CYTHERACEA The only Cytheracea found in oligohaline waters was Limnocythere ?sanctipatricii Brady and Robertson (Text-fig. 3). King and Kornicker (1970) and Hulings (1958) reported L. sanctipatricii living in the a-meschaline to the hyperhaline zone, so it is remarkable that the distribution in Southwest Florida is limited to the oligohaline. In only one station two specimens were found at a salinity of 12.2 o/oo. Therefore, it seems that this form is holeury- haline. Another euryhaline genus is Cyfrideis. In Southwest Florida the most common mesohaline form is Cyprideis ?bcaveni Tressler and Smith (Text-fig. 3). In some areas this species was found in such an abundance as to form an important element of the substrate. It occurs in oligo-, meso-, poly- and euhaline waters. A second species, Cyprideis salebrosa van den Bold (Text-fig. 3), was present in only one sample, remarkably living in fresh water. Sandberg (1964) reported that living specimens occur, but he did not find one with appendages. Hartmann (personal communication) had some soft parts in his sample taken from the Rio de la Plata, but the salinity of this station is not known. Thus, it is questionable whether this species occurs living only in freshwater or also lives in brackish water. Nearly as frequent as Cypridcis ?beaveni is ? Haplocytheridca setipunctata (Brady) (Text-fig. 3). This species is easily distinguished from other species of Cyprideis by means of their unique copulatory organ. This species ob- viously avoids the oligo- and a-mesohaline zone but is found continuously up to the euhaline. ?Haplocytheridea setipunctata is found only in sandy sub- strate. On this substrate Cypridcis ?beaveni can cbviously not compete with ? Haplocytheridea setipunctata. H. setipunctata has been reported from the Gulf Coast and Atlantic Coast of North America. Perissocytheridca ?brachyforma Swain (Text-fig. 3) is another brackish- water species, common in Floridian waters. It was found in the meso- and polyhaline zone in different types of substrate. It probably prefers harder ground, while Perissocytheridea ?bicelliforma Swain (Text-fig. 3) is often found in softer substrate, but also in the meso- and polyhaline district. P. 2brachyforma is very common in the Gulf and Caribbean but has not been reported from the Pacific Coast as has P. ?bicelliforma. Aurila conradi (Howe and McGuirt) has also been reported from both coasts of the North American continent (Text-fig. 3). Living specimen were found at the transition to the oligohaline which concurs with the findings of Kornicker and Wise (1960). Their findings were that the salinity tolerance of A. conradi littorala Kornicker and Wise, 1960 is 6 0/00 to 65 o/oo below at a lower salinity it should become inactive. It prefers obviously hard ground which can be hard detritus, sand or sometimes rock or oyster reefs. Xestoleberis sp. A (Text-fig. 4) was found at times to be associated CANDONA ANNAE CYPRETTA BILICIS CYPRIA PSEUDOCRENULATA Poi SSS CYPRINOTUS SPEC IT PARAPONTOPARTA SPEC. A PARAPONTOPARTA SPEC B PARAPONTOPARTA SPEC. C IMNIC) OLIGO- ALINE pie $i ME SOHALINE POLY- | FIG2 SALINITY RANGE OF CYPRIDACEA ALINE HALINE i) OLIGO- Berd 3 ME SOHALINE pati (Se he PERTISSOCYTHERIDEA AURILA CONRADI FIG3 SALINITY RANGE OF CYTHERACEA 496 D. Keyser with 4urila conradi. Xestoleberis sp. A was present from mesohaline to polyhaline waters. It is remarkable that this form also lives at the transition to the oligohaline zone. This shows it also to be an euryhaline form. It does not occur in mud also comparable to Aurila conradi. Three species of Cytherura were encountered in the mangrove region of Southwest Florida (Text-fig. 4). Cytherura elongata Edwards and Cytherura johnsoni Mincher were found in meso- and polyhaline waters, while Cytherura forulata Edwards was only present in a-mesohaline to euhaline samples. C. elongata was usually found to have larger number of individuals as the re- maining species at the location. They all prefer the same substrate, mostly sand and some detritus. C. elongata and C. forulata are known from the Gulf Coast northwards to southern Virginia. C. johnsoni has also been reported from the Caribbean sea and the Pacific Coast. Two species of brackish-water ostracodes are nearly unknown. Puri (1960) described one species as Reticulocytherecis floridana Puri. I called the other Reticulocythereis sp. 11 (Text-fig. 4). Both are living in a-meschaline to poly- haline water, on sandy ground covered with some detritus. Both species occur together, the soft parts indicate different feeding habits. RESULTS This study represents the ecologic distribution of 20 brackish-water ostra- code species, which were collected between August 20, 1969, and April 4, 1970, at a regular monthly interval in the mangrove region of Southwest Florida. The distribution has been examined mainly in the oligo- and mesohaline zone by examination of living specimens. 1) As typical limnic and oligohaline Cypridacea were identified Candona annae Méhes, Cypretta bilicis Furtos, and Cypria pseudocrenulata Furtos. The latter two have been found occasionally in mesohaline waters but are not believed to reproduce there. 2 ~— A typical form of the Cypridacea in the a-oligo- and f-mesohaline is Cyprinotus sp. II. 3) As new for the Gulf Coast Cypridacea I have reported the genus Paraponto- ~~ parta. Three species were found in the 6-mesohaline and in the polyhaline exclusively, as previously known for the Thalassocypridini. 4 ~— Only three species of Cytheracea were found in salinity lower than 4 0/oo: Limnocythere ?sanctipatricii Brady and Robertson, Cypridcis ?beaveni Tressler and Smith and only limnic Cyfridecis salebrosa van den Bold. 5) ?Haplocytheridea setipunctata (Brady), Perissocytheridea ?bicelliforma Swain, Perissocytheridea ?brachyforma Swain, Aurila conradi (Howe, and McGuirt), Xestoleberis sp. A, Cytherura elongata Edwards and Cytherura johnsoni Mincher showed clearly that they are not able to tolerate oligo- haline waters. 6) The minimum salinity for Cytherura forulata Edwards, Reticulocythereis floridana Puri, and Reticulocythereis sp. II is the a-mesohaline. MESOHALINE lig ! HALINE LIMNI OLIGO- LINE B i B PA pee LY eee an OS eA GE SIZES [FEST (EPS Sn ee FLORIDANA Stage BD &, Y, yaa * ee - \ WWE I) Nov Sataa~ = | => Sa ee RETICULOCYTHEREIS SPEC. II FIG.4 SALINITY RANGE OF CYTHERACEA 498 D. KEYSER ACKNOWLEDGMENTS I would like to thank Prof. Dr. G. Hartmann, Zoologisches Institut und Museum, Universitat Hamburg, and Dr. H. S. Puri, Florida Department of Natural Resources, Bureau of Geology, Tallahassee, Florida, for the most valuable help during the study and the preparation of the manuscript. Gratitude is also expressed to the Florida Bureau of Geology and the Everglades National Park which made it possible to collect the material and were very helpful in many problems. I want to give my thanks also to the Florida State Uni- versity which offered me the use of their instrumental facilities. REFERENCES Furtos, N. C. 1936. Fresh-water Ostracoda from Florida and North Carolina. Ameti- can Mid. Nat., 17, pp. 491-522. Hartmann, G 1955. Neue marine Ostracoden der Familie Cypridae und der Subfamilie Cytherideinae der Familie Cytheridae aus Brasilien. Zool. Anzeiger, Bd. 154, Heft 5/6, pp. 109-127. Hulings, N. C. 1958. An ecologic study of the Recent ostracods of the Gulf Coast of Florida. Unpublished Dissertation Florida State University, Talla- hassee, Fla. King, C. E., and Kornicker, L. S. 1970. Ostracoda in Texas Bays and Lagoons: An Ecologic Study. Smith- sonian Contrib. Zoology, No. 24, pp. 1-92. Klie, W. 1938. Ostracoda, Muschelkrebse. In F. Dahl, Die Tierwelt Deutschlands und der angrenzenden Meeresteile, 34 (3), pp. 1-230. Kornicker, L. S., and Wise, C. D. 1960. Some Environmental boundaries of a marine ostracode. Micro- paleontology, 6 (4), pp. 393-398. Puri, H. S. 1960. Recent Ostracoda from the west coast of Florida. Gulf Coast Assoc. Geol. Soc., Trans., vol. 10, pp. 107-149. Puri, H. S., and Benda, W. K. 1962. The distribution of Foraminifera and Ostracoda off the Gulf Coast of the Cape Romano area, Florida. Gulf Coast Assoc. Geol. Soc., Trans. vol. 12, pp. 303-341. Sandberg, P. A. 1964. The ostracod genus Cyprideis in the Americas. Stockholm Contrib. Geology, vol. XII, pp. 1-178. Swain, F. M. 1955. Ostracoda of San Antonio Bay, Texas. Jour. Paleont., vol. 29, No. 4 (July), pp. 561-646. Tressler, W. L., and Smith, E. M. 1948. An ecologic study of seasonal distribution of Ostracoda, Solomons Island, Maryland, Region. Chesapeake Biol. Lab., Pub. 71, pp. 3-57. Dietmar Keyser, Zoologisches Institut und Museum, Hamburg, Germany Soutu FLoripA MANGROVE OsTRACODES 499 DISCUSSION Dr. L. S. Kornicker: I would like to commend you on an excellent paper. The question I have is whether you satisfied yourself by examining the West Coast specimens, that those you found on the East Coast and the West Coast were conspecific or are you relying on literature? Mr. Keyser: At this moment I am still relying only on literature. But I agree that this is necessary, if one wants to give reliable zoographical data. Dr. H. Léffler: I am glad that you put a question mark on sanctipatricti, For I don’t think that your Limnocythere is sanctipatricii, which is known to be a cold water species. Mr. Keyser: I think you are right, but I named it sanctipatricii for this species has been referred to in all papers I know of as Limnocythere sanctipatricit. The question mark should accentuate my disbelief that this is the same species as the European. Dr. J. E. Hazel: I think that this work will be valuable not only in under- standing mangrove environment but also in interpreting many Pleistocene deposits in Florida that have assemblages somewhat similar to what you described. I would like also to say that we have many of the same species in common, and we're not in all cases using the same names for them. We should get together and get the nomenclature sorted out. Dr. H. Uffenorde: How close to the bottom-dwelling ostracodes did you measure salinity? In sheltered marginal marine environments a rapid decrease in salinity from bottom to top can be observed within a few decimeters. If there is any fresh water supplied by brooks, springs, or rain it may form a covering layer of fresh water. Mr. Keyser: I used a portable conductivity meter. So I was able to measure the salinity directly above the bottom. To your other remark I would like to say, that the area in which I was sampling is a lagoonal type of environment, and there you find conditions which are mainly influenced by tidal currents and to a lesser extent by fresh water streams. King and Kornicker (1970) mentioned in a similar area that the bottom and surface salinity do not differ extensively, less than 1/10 of a part per thousand. Dr. R. Reyment: My comment follows the preceding remark (by Uffenorde). As has been demonstrated by F. Manheim, R. Hallberg (1972; Diss. Univ. Stockholm), Hallberg and Reyment (Crustaceana, 1967), and Reyment (Bull. Geol. Univers. Instn. Upsala, 1969), the ecochemical conditions prevailing within the sediment (interstitial pore water) and in which many organisms live, including ostracodes, differ considerably from those existing in the super- natant water. Dr. Uffenorde: I agree with Dr. Reyment’s remarks. I fear we are heading the wrong way using methods developed by oceanographers to get data for areas a thousand and more times bigger than the ostracode habitat. This is true especially for measurements of oxygen saturation and redox potential. 4 ton i i: ei Nate an : | baila ri ait t ws [roe 7 : 7 : <> ANA wor te [dale se hay j ; ‘| eAit I his a é mB een a nao i : iyid Nib eazeh ered vere a aves 2 ma) . Dit: ef ywapi (eae, ivi rhe ae ey rma ee, 8 #00 vet hin : i es iF ath a i, ae Tong ¥ a fe . ore, ail 9 bial we ¥ 7 Har oe THE FAMILY LEPTOCYTHERIDAE IN ARGENTINE WATERS R. C. WHATLEY Universidad Nacional de La Plata and University College of Wales and A. MocuILevsky Universidad de Buenos Aires ABSTRACT Eight species, belonging to two genera of the Leptocytheridae, are herein recorded from the Argentine Continental Shelf and from adjacent littoral, estuarine, and lagoonal environments. Five of these species are new: Lepto- cythere, n. spp. A, B, Callistocythere, n. spp. A, B, C, but are not formally named or described here. Another species of Leptocythere is also left with open nomenclature. The geographical ranges of L. patagonica and C. disperso- costata previously recorded from Patagonia by Hartmann (1962), are ex- tended northwards. Distributional and ecological data are given for each species and it is noted that the majority of species of both Leptocythere and Callistocythere are more phytal in their habit in these waters than is normal for the members of the two genera elsewhere. A note is also included on the known fossil history of the family in this part of South America. RESUMEN Se reconocen 8 especies, pertenecientes a 2 géneros de Leptocytheridae, en la Plataforma Continental Argentina y en ambientes adyacentes de tipo estuarico, litoral y de albufera. De estas especies, 5 son nuevas: Leptocythere n. spp. A, B, Callistocythre A, B, C, y una especies de Leptocythere se incluve bajo nomenclatcra abierta. Se amplia hacia el norte la distribucién geografica de L. patagonica y C. dispersocostata, mencionada con anterioridad para Pata- gonia por Hartmann (1962). Se incluyen, ademas, detalles de la ecologia y distribucion de cada una de las especies. Observandose que la mayoria de las especies de Leptocythere y Callistocythere de estas aguas son mds comunmente epifiticos que otros miembros de los mismos géneros en otras regiones. Se incluyen algunas consideraciones sobre la historia geologica de la familia Leptocytheridae en este parte de America del Sud. RESUME On reconnait 8 espéces, appartenent a 2 genres de Leptocytheridae, sur la plateforme continentale argentine et sur les milieux adjacents de type littoral estuaire ou lagune. De ces espéces, 5 sont nouvelles: Leptocythere, n. spp. A, B, Callistocythere, sp. A, B, C, et ume espéce de Leptocythere est laissée dans une nomenclature ouverte. La distribucion géographique de L. patagonica et C. dispersocostata, mencionnées antérieurement en Patagonie par Hartmann (1962) s’étend vers le nord. De plus des détails concernant l’écologie et la distribution de chaque espéce ont été inclus. On peut noter que la plus grande partie des especes de Leptocythere et Callistocythere en provenance de ces eaux sont plus communément epiphytiques que d’autres membres des mémes genres en d'autres régions. On a égalment inclus une note sur l'histoire géologique les Leptocytheridae dans cette région d’'Amérique du Sud. INTRODUCTION The present work forms part of a comprehensive monographic study concerning the taxonomy, ecology, and zoogeographical distribution of ben- 502 R. C. WuaTLey anp A. MoGuiLevsky thonic Ostracoda from the Argentine continental shelf and from adjacent littoral and estuarine environments. This study is based on samples collected by the Argentine Institute of Oceanography and the Hydrographic Service of the Argentine Navy, from the continental shelf and from the estuary of the River Plate (Rio de La Plata) and samples collected by the authors, at various intervals during 1970 to 1972, from estuarine and littora] environments be- tween the River Plate and Tierra de] Fuego (Text-fig. 1). This latter sampling also embraces southern Chilean water, especially in the Straits of Magellan. The sediment samples from the continental shelf have been collected by means of both “grab” and “dredge”, and those from the littoral by standard techniques for collecting sediments and by the processing algae as described by Whatley and Wall (1969, p. 294). Sublittoral weed and sediments have been collected by dredging and by diving. Relatively few works exist concerning the benthonic Ostracoda of Argen- tine and adjacent waters, and even fewer contain descriptions of the family Leptocytheridae. From the Argentine the only two species which have been described previously, both from Patagonia, are Callistocythere dispersocostata Hartmann, 1962, and Leptocythere patagonica (Hartmann, 1962), who also mentioned another, Callistocythere sp., also from Patagonia and Tierra del Fuego. The same author has described the following species from Brasil: Callistocythere ornata (Hartmann, 1956) Callistocythere sp. (Hartmann, 1956) Callistocythere costata (Hartmann, 1956) Mesocythere foveata Hartmann, 1956 Mesocythere clongata Hartmann, 1956 Mesocythere punctata Hartmann, 1956 Ilyocythere Klie, is excluded from this list because the authors are of the opinion that it is probably synonymous with Perissocytheridea Stephenson. Pericythere is similarly excluded since, by virtue of its unbranched marginal pore canals and adont hingement, it would not seem to belong to the Lepto- cytheridae. From Chile, Hartmann recorded both C. dispersocostata and L. patagonica (Hartmann, 1962) and also C. fischeri (Hartmann, 1961). In the present study, three new species of Callistocythere and two of Lepto- cythere are added to the list for the family in these waters. Also, a further species of Leptocythere is left with open nomenclature. That the family Leptocytheridae has a fossil history in the Argentine is evidenced by the occurrence of two species of Mesocythere in sediments of upper Oligocene/lower Miocene age from the eastern part of the Province of Santa Cruz, Patagonia, (Lic. Hugo Valicenti, personal communication), by the occurrence of Callistocythere in Miocene sediments from the Province of Entre Rios (the material described by Rossi de Garcia (1966) as Perissocytheridea littoralensis is certainly Callistocythere as illustrated in Plate 2), and by the occurrence in Pleistocene and Holocene sediments in the Province of Buenos Aires of C., n. sp. A (Whatley unpublished). All types and figured specimens caaaaia” 4 7 ee AwNonyn . 7 : f alt } ne as a + eo : eee gh , et a a » Fh seed ae Ph wah) : wv . " urs i 4 «7 ‘ rer a ‘> 1 ee , w . : a tw + 989 i nt Set sive vivid 120 uvW 90/arw, BEA de “® Bazi saw? isa “nw O3GIAZLNO AWwnonun “ soGvis2 sols MA) NwVJs0"m 40 Gilwuss &o AbWwwis tid [tvmiaryn) Sonvie: Onviniwe <> Aa Pee reeee® + aneanHo 40 a9 WTaoud ee ee ee ee me ee ee — Heese te a se 0e* Penetee® Tetee . . . ARGENTINE LEPTOCYTHERIDAE 503 are deposited in the collections of the Department of Palaeontology, Museo de La Plata, to which the numbers quoted in the paper refer. Topotype or reference material has also been deposited in the British Museum (Natural History), the U.S. National Museum and the Argentine Museum of Natural Sciences, Buenos Aires. ACKNOWLEDGMENTS R. C. Whatley wishes to acknowledge the support of the Argentine Con- sejo Nacional de Investigaciones Cientificas y Técnicas, and A. Moguilevsky the support of the Facultad de Ciencias Exactas y Naturales, University of Buenos Aires. The authors wish particularly to thank Lics. Maria Luz Piriz and Alicia Boraso for assistance in collecting and identifying algae and extend the same thanks to their companions on the 1971 expedition to Patagonia, especially to Sr. Miguel Mancenido for his services as diver and also for col- lecting the material on the cruise of the Austral. From the Hydrographic Service of the Argentine Navy, the authors have received many kindnesses and much valuable material and data. We wish particularly to acknowledge the help of Capt. Ascencio Carlos Lara, Teniente Osvaldo Bozzo, and Sr. N. Randich. Equally, we are extremely grateful to the Argentine Institute of Oceanography, Bahia Blanca, for all their assistance, especially from Ingeniero Alberto Lonardi and Lic. Felix Mouzo. Permission to use the facilities of the Argentine Centro de Investigaciones de Biologia Marina del I.N.T.I., in Puerto Deseado and Ushuaia, kindly granted by the director, Dr. Oscar Kuhnemann, is grate- fully acknowledged. Valuable discussions have been held with many workers in various fields but the authors particularly wish to mention Dr. Estaban Boltovskoy, Dr. Raul Santiago Olivier, Dra. Zulma Castellanos and Lic. Hugo Valicenti, who also helped with the photography. Lic. Lucy Costa and Sr. Jorge Mennucci have also helped the authors in many ways. The SEM photography was executed with the CONICET instrument. Finally, R. C. Whatley wishes to extend his warmest thanks to the British Council for financing his visit to Delaware and to his collegues in the University College of Wales, Aberystwyth, for their prompt response to many strange and varied requests. GEOGRAPHICAL LOCATION AND DESCRIPTION OF THE SAMPLES Although approximately 400 samples have been examined to date in our study of the Argentine benthonic Ostracoda, Leptocytheridae have only been found at the following 37 localities, of which 22 are littoral and the remainder on the continental shelf or from the entrance to the estuary of the River Plate (Text-fig. 1.) 504 R. C. WuaT ey Anp A. MoGulILEvskKy a) Littoral 1) Santa Elena. Approximately 20 Km. north of Mar del] Plata, Province of Buenos Aires. Red and green algae collected at low tide in February, 1971, from a lower eulittoral rock platform. The algae contained coarse to medium sand and shell fragments. Very exposed coast with strong wave action. C., n. sp. A (dead) @. 2) Playa Grande. Mar del Plata, Approximately 38°S. Algae and sediment collected from a eulittoral rock pool immediately to the north of the Marine Biological Station, September 1970. C., n. sp. A 92, ng. & sp. Q, and Lepto- cythere sp. (all dead). 3) Pocitos. Approximately 30 Km. north of Bahia San Blas in the extreme south of the province of Buenos Aires at about 40°25’S. In this area, which is very sheltered by a series of offshore shoals and islands, exist a variety of littoral environments ranging from rock platforms and mud flats in the eulit- toral and sublittoral, to dense clumps of Spartina growing in the upper eulittoral and in the littoral fringe. PO/1. Fine sand and silt from roots of Spartina. C., n. sp. A @ (live), EAMESpae Ae Gn o) Wives live) me e|anuanynl 97 Le 4) Punta Ramirez. Approximately 10 Km. south of the preceeding locality and similarly protected by offshore shoals and islands. Extensive eulittoral and sublittoral rock platform, with Spartina growing in the littoral fringe and upper eulittoral. The following samples collected in January, 1971, yielded Leptocytheridae. PR/3. Upper sublittoral or lower eulittoral algae growing on stones at the bottom of a channel. L., n. sp. A @ (dead). PR/4. Eulittoral algae from rock pool. C. dispersocostata 6 @ (live), Lan-sp. Ag) r Sc (live)! PR/11. Upper eulittoral, Ulva, Enteromorpha, and sediment from a rock pool. G. dispersocostata ¢ © (live), Cn. sp. A 2 (live) Ge neaspeee @ (dead), L., n. sp. A @ @ (live). PR/13. Littoral fringe or extreme upper eulittoral. Sediment from around roots of Spartina growing in a shallow pool. C. dispersocostata 6 @Q juv. (live), G., nu. sp. © 9 (live), LE. patagontca 9 (dead), Ln. sp» Ad G juves(lime)e n.g. & sp. 9 (dead). 5) Arroyo Jabali. Shallow muddy tidal ria-like inlet of the sea behind the village Bahia San Blas, Province of Buenos Aires, apparently without fresh- water-connections and probably highly saline after protracted hot weather. January, 1971. Ao/1. Algae and algal detritus collected from below low water mark. C. dispersocostata (dead), L., n. sp. B (smooth form) @ @ juv. (live). Ao/3. Fine sand and silt with much organic, particularly algal detritus, just above low water mark. Z. n. sp. A ¢@ @ juv. (live), C., n. sp. A ¢ 9 (live), C., n. sp. C @ (live). 6) San Antonio Oeste. Province of Rio Negro, approximately 40°40’S. Large ria immediately south of the town. Algal sample of Bryopsis, Ceramium, and Ulva from stones in the lower eulittoral at the base of a steep shingle beach, February, 1972. L., n. sp. A 6 @ juv. (live), C. dispersocostata 6 @ (live). ARGENTINE LEPTOCYTHERIDAE 505 7) Las Grutas. Province of Rio Negro, a few Km. south of San Antonio Oeste. Eulittoral rock platform to the immediate south of the Esplanade. Leptocytheri- dae collected from the following samples in January 1971: SA/1. Lower eulittoral. Codium from small rock pool. C. dispersocostata Ceo (live) hl m-ispe Dard OS ajuv. (live), Cim- spx'© Os (live) SA/2. Sediment of sand, small pebbles, and shell detritus from the same pool. C. dispersocostata 6 @ juv. (dead). L., n. sp. A g @Q juv. (dead). Gone sp. © Q” (live): SA/3. Assorted smaller algae, including Polysiphonia, Ceramium, and Entcromorpha from the same pool. C. dispersocostata 6 @Q (live), C., n. sp. C @ (live). L., n. sp. A 6 Q juv. (live), ZL. patagonica 2 (dead), n.g. & sp. 6 (dead). SA/5. Rhodophyceae from a number of lower eulittoral pools in the same area. C. dispersocostata 6 @ (live), C., n. sp. C Q@ juv. (dead) L., n. sp. A 6 Q juv. (live). 8) Isla de Los Pajaros (Bird Island). On the southern shore of Golfo San José, Peninsula de Valdez, Province of Chubut, approximately 42°25’S. Eulit- toral rock platform and mud flats on the mainland shore facing the island. Protected shore due to the presence of the Island. Leptocytheridae obtained from three of the nine samples. BI/1. Algae from small 1-foot-deep rock pools in the upper eulittoral surrounded by tussocks of Spartina. C. dispersocostata 9 (live), L., n. sp. A $ @ juv. (live), L. patagonica 2 (dead), L., n. sp. B (smooth form) ¢ @ juv. January, 1971. BI/5. Corallina, Ulva, and Polysiphonia, collected from three pools in the mid or lower eulittoral. C. dispersocostata 6 @ juv. (live), C., n. sp. A Q (ive) ,ei ene sp. Ads 2 Tlie): 9) Punta Norte. Northern tip of Peninsula Valdez? Province of Chubut, ap- proximately 42°05’S. Exposed coastline with a lower eulittoral rock platform with dense algae beneath a steep shingle beach. Samples taken immediately to the south of the Elephant Seal (Muirounga leonina) colony administration buildings. PN/1. Blidingia and Porphyra from rock platforms. C. dispersocostata juv. February, 1972. 10) Caleta Valdez. Elongate tidal lagoon separated from the sea by a shingle spit with a narrow entrance and apparently without fresh-water influence, on the eastward facing side of Peninsula Valdez, Province of Chubut, at about 40°20’S. Sample of fine calcareous mud with algal debris taken from sub- littoral. C. dispersocostata $ 2 juv. (live), L. patagonica 8 Q (live). 11) Punta Delgada. Southeastern tip of Peninsula Valdez, 42°47’S. Extensive eulittoral rock platform terminated by a vertical drop to the sublittoral. Pd/1. Assorted algae from upper eulittoral rock pool. C. dispersocostata oo 2 a(dead) ReGs ne spy Cy?) “(livie): Pd/4. Green algae, principally Enteromorpha, from upper eulittoral rock pools. C. dispersocostata 2 juv. (live), Z., n. sp. B (smooth form) @ @ (live). Pd/7. Codium from lower eulittoral. ZL. n. sp. B @ juv. (live). Pd/8. Red algae from upper eulittoral pools. C. dispersocostata 6 @Q juv. (live). Z., n. sp. B (smooth form) @ (live). Pd/9. Corallina from the same pools. C. dispersocostata 6 @Q juv. (live) L., n. sp. B (smooth form) ¢@ juv. (live). Pd/10. Mid-eulittoral Phaeophyta growing above “mattress” of Corallina and mussels. C. dispersocostata Q (live). January, 1971. 506 R. C. Wuattey anp A. MocuiLevsky 12) Punta Ameghino. On the northwestern shore of Golfo Nuevo, Province of Chubut, a few Km. N.E. of Puerto Madryn at about 42°37’S. Eulittoral rock platforms with many pools. Lower eulittoral algae, Ceramium, Polysiphonia, Corallina, Codium vermilare, and Codium fragile. C. dispersocostata $ @ juv. (live). February, 1972. 13) Bahia Solano. Algae collected from rock pools approximately midway be- tween Caleta Cordoba and Pico Salamanca at about 45°42’S. and some 20- 25Km. north of Comodoro Rivadavia, Province of Chubut. C. dispersocostata Q (live). L., n. sp. B S @ juv. (live), L. patagonica $ @ (live). March, 1972. (Collected by Lic. Hugo Valicenti). 14) Caleta Olivia. Province of Santa Cruz, wide bay a few Km. south of the town at about 46°30’S. Extensive eulitteral rock platform. Sediment sample of medium to coarse sand and shell debris from lower eulittoral channels in the rock platform. C. dispersocostata & @2 (dead), L. patagonica Q (dead). February, 1972. 15) Puerto Deseado. 47°45'10” S. Province of Santa Cruz. From several hundreds of eulittoral and sublittoral samples taken from within the Ria and from immediately outside it, from both algae and sediments, the following Leptocytheridae have been recorded: C. dispersocostata @ @Q juv. (live), Le eispeab a2 juve wpatagonical 6.19. juve n(liye)r 16) San Julian. Province of Santa Cruz, at about 49°18’S. Large Ria without fresh-water influence. Immediately to the S.E. of the town, on the N. side of the Ria, steep muddy and stony eulittoral beach with, in the lower part, dense algal growth on stones. Sample of Enteromorpha, Ceramium, Porphyra, and a little U/wa. L. patagonica & Q juv. (live). January, 1972. 17) Monte Leén. 50°18’S. Beach sample of sand and algal detritus. C. disperso- costata Q (dead). 18) Rio Gallegos, Province of Santa Cruz, at about 51°38’S. Large estuary in which the tidal element is dominant. Sample of fine-grained lime mud taken at low water on the south bank of the estuary near the eastern limit of the town. C. dispersocostata Q (live). January, 1972. 19) Cabeza del Mar. Province of Magallanes, Chile at about 52°45’S. and some 55 km. north of Punta Arenas. Large shallow enclosed bay opening off from the west coast of the Straits of Magellan, with small tidal amplitude. Samples taken in the eulittoral immediately in front of Chorrillo La Lata Estancia. Talusa parda, Ceramium, and Enteromorpha with many epiphytes, growing on stones and also the adjacent sediment. L. patagonica 6 @ juv. (ive); 25 nbsp. B62 juv, (live)e January, 1972: 20) Puerto Porvenir. Province of Magallanes, on the east side of the Straits of Magellan, in Chilean Isla Grande (Tierra del Fuego), at about 53°16’S. Nar- row ria-like inlet with little fresh-water influence. Samples taken some 3 Km. west of the town on the northern side of the inlet, Rocky beach with algae growing on stones in the lower eulittoral, well protected by the narrow nature of the inlet and by dense growths of Macrocystis in the immediate offshore sublittoral. Porv./2. Green algae, mostly Cladophora, from lower eulittoral. L. pata- gonica 3 Q (live), C. dispersocostata @ (live). January, 1972. 21) Estancia Viamonte. Argentine Tierra del Fuego, on the northern coast of Isla Grande at about 53°56’ S. and some 20-25 Km. S.E. of Rio Grande, and ARGENTINE LEPTOCYTHERIDAE 507 some 5 Km. east of the Estancia buildings. Very exposed coast with large tidal amplitude exposing wide mud and sand flats with isolated pebbles and boulders which bear algae. Via/1. Eulittoral Enteromorpha, L. dispersocostata (live). January, 1972. 22) Ushuaia. Argentine Tierra del Fuego, on the northern coast of the Beagle Channel at about 54°50’S. From the large number of samples taken in this area January, 1972, Leptocytheridae were found in the following: USH/4. From Bahia Golondrina, 5 Km. to the west of the town. Macro- cystis holdfasts from the upper part of the sublittoral. L. patagonica g 2 (live). USH/8. From the same locality, lower eulittoral Enteromorpha. L. pata- ponica 6 @ (live), C. dispersocostata 2 (live). b) Sediment samples from the continental shelf and from the estuary of the River Plate. 1) Almirante Saldanha/1252. 36°05’S. 56°17'05”W. 23 Fm. Grab sample, fine to medium shelly sand. M. foveata 2 (dead). 2) Rio de La Plata/59. 36°11’S. 56°58’08”W. 3 1/2 Fm. Grab sample, silty mud with many broken shells. C.n. sp. A @ @ (dead), n.g. & sp. ¢ @ (dead). 3) Rio de La Plata/61. 36°12’09”"S. 56°58’08”W 3 1/4 Fm. Grab sample, fine silt and mud with small shells and comminuted shell fragments. n.g. & sp. Cae oeuve(dead) Gains spb G2. (dead). 4) Pesqueria V/26. 36°12’40"S. 56°24’08”W. 10 Fm. Grab sample, dark medium to fine sand with shell fragments. M. foveata 2 (dead), L. patagonica Q (dead), Leptocythere sp. (dead). 5) Rio de La Plata/64. 36°15’05"S. 56°55’05”W. 2 1/4 Fm. Grab sample, muddy silt with fine comminuted shell fragments. C. dispersocostata 2 (dead), Cains sprpieG 2 a(dead)i Gon. sp: eA oo (dead) = mes & sp: 6 2 (dead) 6) Almirante Saldanha/1245. 38°11’S. 56°56’05” W. Grab sample, fine to medi- um poorly sorted sand with shell fragments. M. foveata § @ (dead), C., n. sp. A @ (dead). 7) Austral/VI/8. 38°41’S. 58°51’W. 80 feet. Dredge sample. Stones encrusted with polyzoa and serpulids, with corals, ascidians, shells, and some fine sand and silt. C. n. sp. A @ (live). 8) Austral/VI/6. 38°54’S. 58°47'°W. 145 feet. Grab sample, medium sand. C. n. sp. A @ (live), n.g. & sp. 6 @ (dead). 9) Austral/VI/13. 38°56’S. 60°03’W. 75 feet. Grab sample, very fine sand and silt) Gs n. sp. A 2 (dead), Z., n. sp. A juv. (dead). me. & sp. 6 2 (dead): 10) Austral/VI/3. 39°02'09"S. 58°24’05”W. 165 feet. Grey medium sand with a few shell fragments. n.g. & sp. 6 @ (dead). Grab sample. 11) Austral/VI/10. 39°10’S. 50°05’W. 140 feet. Fine to medium shelly sand. ng. & sp. 6 @2 (dead). 12) Austral/VI/15. 39°17’S. 60°27’W. 115 feet. Grab sample, fine sand with some shell fragments. n.g. & sp. ¢ @ (dead). 508 R. C. WuaTLey ANp A. MocuiILevsky 13) Austral/VI/23. 39°20’S. 61°40’W. 40 feet. Grab sample, fine sand. M. foveata 2 (dead), Leptocythere sp. (dead), L. patagonica Q (dead), C., n. sp. B @ (dead). 14) Austral/V1I/14. 39°32’S. 60°20’W. 135 feet. Dredge sample, coarse to medi- um sand with many shells and fragments. Leptocythere sp. (dead). 15) Austral/VI/21. 39°45’S. 61°53’W. 45 feet. Grab sample, medium sand with some shell fragments. C., n. sp. A 6 @ (dead), L., n. sp. A Q (dead), n.g. & sp. 2 (live). 16) West Wind/95, 42°23’S. 62°43’W. 31 Fm. Grab sample, very fine sand to silt with many Foraminifera and comminuted shell fragments, n.g. & sp. Q (live). 17) Pesqueria/XI/6. 44°40709"S. 60°04’09”W. 60 Fm. Grab sample, fine silty sand with large shell fragments. L. patagonica 2 (dead). SYSTEMATIC DESCRIPTIONS Family LEPTOCYTHERIDAE Hanai 1954 Discussion. —Included in this family are the genera Leftocythere Sars, Callistocythere Ruggieri, Mesocythere Hartmann, and Tanclla Kingma. The present paper concerns members of the first two. Leptocythere and Callistocythere species are normally readily distinguish- able and separable in that they differ in the following respects: Callistocythere is shorter, wider, and more heavily calcified than Leptocy- there and whilst the former is strongly ribbed and tuberculate or tuberculate, the latter is usually punctate or even smooth. The hinge of the two genera also differs in that in Callistocythere the hinge is more robust and contains, antero- medially in the left valve, two or more distinct denticles which are reflected in the opposite valve, whilst Leptocythere bears a single tooth antero-medially in the left valve which, if it is complemented in the right valve, this latter sock- et is always very weakly developed. The selvage locking “snap knob and pit mechanism of the ventral margin is always well developed in Callistocythere whereas it is absent, or only feebly developed in Leftocythere. Additionally the vestibulae of Leptocythere are discrete and better developed than in Callis- tocythere, which latter also exhibits less symmetrically developed marginal pore canals. Whilst both genera have essentially similar appendages, the posterior termination of the body of the females of Leptocythere is usually more rounded than that of Callistocythere which usually bear hooked, ventrally directed projections. Whilst the majority of the species can be assigned to one or another of the two genera without difficulty, there exist a number of species which combine characteristics of the two genera and which are not really assignable. As pointed out by Wall (1969) Cythere macallana Brady, (1869) is morphologi- cally intermediate between the two genera, although in summation of its biocharacters, it is probably slightly closer to Leptocythere. L. patagonica Hart- ARGENTINE LEPTOCYTHERIDAE 509 mann and C., n. sp. C are another two such forms. Such intermediate species are commonly responsible for the creation of new taxa, or for the restriction or expansion of existing generic diagnosis. For the present, the authors prefer to await a greater knowledge of the two genera, based on a restudy of existing species before advocating any of the possible alternatives. Hanaj (1957) also makes geographical and ecological distinctions between the two genera in considering Callistocythere as predominantly a marine warm water group and Leptocythere as a cold water brackish group. This is far too much of a generalization and there are very many exceptions to the rule. C., n. sp. A, is for example, in the Argentine context, a warm water northern species, yet it is equally common in brackish environments as it is in marine ones. Indeed, in Holocene brackish Jagoonal environments in the northern part of the Province of Buenos Aires, it formed the dominant part of the ostracode fauna, together with Cyfridcis, Paracytheroma, and Limnocythere. (R. C. Whatley unpublished). Similarly, J. E. Whittaker (personal communi- cation) records Callistocythere commonly in brackish-water environments along the English south coast, often in substantial numbers. Additionally. C. dis- persocostata Hartmann, is in South American terms, a cold water southern species being commonly encountered in Tierra de] Fuego and southern Chile. Such species as Leptocythere tenera (Brady & Norman) 1889, Leptocythere sp. 3 Whatley, Whittaker and Wall 1971), together with Leptocythere sp. recorded herein, are exclusively marine forms, often being restricted to rela- tively deep water. From this it would seem that whilst the majority of species of Callistocythere are marine and of low latitudes, and the majority of Lepto- cythere of high latitudes and able to tolerate reduced saline environments, there is probably much more biogeographical and ecological overlap of the two genera than previously thought. Genus LEPTOCYTHERE Sars 1928 Leptocythere patagonica Hartmann, 1962 Plate I, figs. 1-3; Plate III, figs. 26, 27 1962. Leptocythere patagonica Hartmann, pp. 199-209, text-figs. 59-69. Remarks. — This species is one of those which in many ways falls between the genera Callistocythere and Leptocythere. The posterior termination of the body of the female most closely resembles Callistocythere. It resembles Lepto- cythere in its shape and in the expression of sexual dimorphism and also in its ornament which is of fairly small uniform punctae. The weak “overprinted” reticulation, illustrated by Hartmann (1962, text-fig. 60), is very difficult to make out on most specimens but is certainly visible on some. The hinge is like that of Callistocythere and is very strongly developed with, anteromedially in the left valve, three strong teeth which are reflected in the antero-median element of the right valve. The ventral “snap knob and pit” locking device is more strongly developed than in other Leptocythere species herein described. 510 R. C. Wuat ey anv A. MoculILevskKy The marginal (radial) pore canals are less regularly symmetrical than in most Leptocythere species and consist anteriorly of three or four large proximal canals, of which the central is largest, which polyfurcate distally. The strong posterior rib is another feature more typical of Callistocythere. Another feature of interest in this species are the normal pore canals which although extremely large in size, are not apparently of sieve-type. The authors, whilst recognizing the fact that this species presents a mixture of the characteristics of Lepto- cythere and Callistocythere, have retained it within the former. The reasons for doing this are not profound, and it is realized that eventually it may be necessary with a better knowledge of both genera to perhaps erect a new taxon to accommodate such intermediate forms or to expand the original diagnosis of either Callistocythere or Leptocythere to accommodate them. It is also interesting to record that the instars very much more closely resemble Leptocythere than do the adults. Material. — Several thousand specimens, of which the majority contain soft parts. Dimensions. — All from Puerto Deseado. Length Height 2 LV MLP 11745/a 0.59 0.325 @ RV MLP 11745/b 0.58 0.32 & RV MLP 11745/c 0.60 0.31 —1 Instar RV MLP 11745/d 0.52 0.29 —2 Instar Carapace MLP 11745/e 0.42 0.23 —3 Instar Carapace MLP 11745/f 0.34 0.20 The instars resemble Leptocythere more than does the adult. The —1 instar has, however, a hinge similar to but much weaker than the adult. All instars are punctate. Distribution and ecology.— Hartmann (1962) recorded this species from Puerto Montt in Chile, in the Magellan Straits near Punta Arenas, and from Puerto Deseado, Province of Santa Cruz, Argentina; all from the eulittoral. In the present study this species can be shown to be principally eulittoral in its occurrence and although it does occur, usually as dead valves, north of Peninsula Valdez, it is not common north of about 42°30’S. It has been found in the following samples: a) Littoral b) Continental Shelf Punta Ramirez (dead) Pesqueria/V/26 (dead) Bird Island (dead) Austral/VI/23 (dead) Las Grutas (dead) Pesqueria/XI/6 (dead) Caleta Valdez (live) Bahia Solano (live) Caleta Olivia (dead) Puerto Deseado (live) San Julian (live) Cabeza del Mar (live) Puerto Porvenir (live) Ushuaia (live) ARGENTINE LEPTOCYTHERIDAE 59 It is probable that this species is entirely littoral and southern in its habit and the records from the north of Peninsula Valdez and from the continental shelf, which are always of isolated dead specimens, are the product of post- mortem transportation. This species, is commonly phytal in its habit but has also been recovered live from eulittoral and sublittora] sedimentary environ- ments in Puerto Deseado. It commonly inhabits “holdfasts” of Macrocystis which plants, due to their possession of “floats”, are commonly distributed northwards by the prevailing northerly Malvinas current which could account for the occurrence of dead specimens as far north as 36°12’09"S (Pesq./v/26). Leptocythere patagonica has not been recorded from environments of re- duced salinity although in at least one locality, Caleta Waldez, its most northern live occurrence, it seems able to exist in waters which in summer are probably somewhat above the level of salinity of the adjacent sea. This species, unlike most other members of the Leptocytheridae herein discussed does not vary throughout its substantial latitudinal range in either size or ornamenta- tion. Leptocythere, n. sp. A Plate I, figs. 4-6; Plate III, figs. 1-7 Dimensions. — Length Height Width LV MLP 11746 0.495 0.255 0.11 Material. — Approximately 1,500 live and 800 dead individuals. Diagnosis.— A small to medium species of Leptocythere with ornament of small circular punctae and weak ribs, the latter being especially prominent anteriorly. Hinge weak and typical of the genus. Medium sulcus oblique and irregular. Remarks. — This species is smaller than L. patagonica, and also differs in possessing finely punctate ornament without an “overprinted” reticulation. Additionally it does not possess a hinge reminiscent of Callistocythere. From L. n. sp. B it differs in its smaller size and more strongly and regularly punctate ornament. It is also more “northern” in its distribution than either of the above named species. Distribution and ecology.— This species occurs very commonly in eulittoral environments between latitudes 40°S and 43°S., it is also recorded, much more rarely, on the continental shelf between about 38° and 39°S. It occurs in the following samples: a) Littoral b) Continental Shelf Pocitos (live) Austral/VI/13 (dead) Punta Ramirez (live) Austral/VI/21 (dead) Arroyo Jabali (live) San Antonio Oeste (live) Las Grutas (live) Bird Island (live) Punta Delgada (live) Although in a number of localities it was collected live from sedimentary environments, except when the sediments are of fine grain, such as at Pocitos 512 R. C. WuaTLey anp A. MocuiILevsky or Arroyo Jabali, it is usually only encountered dead in such environments. The species is dominantly phytal in habit and has been found inhabiting a variety of weeds in eulittoral rock pools. The two records from the continental shelf, in both cases of single dead specimens, are thought to be the product of post-mortem transportation, probably by attachment to floating weed. Al- though there is some degree of variation in the ornamentation, some individuals being less strongly or less uniformly punctate than the majority, this does not seem to be linked, as it is with Z. n. sp. B, to geographical or en- vironmental factors. No size variation is apparent in this species, which, in the Argentine context, is a northern form, and throughout much of its range it is the only known species of the genus. In the southern part of its range it overlaps, in Peninsula Valdez, with the smooth northern form of L., n. sp. B, and to a lesser extent with L. patagonica. Leptocythere, n. sp. B Plate I, figs. 7-11; Plate III, figs. 8-15, 20 Dimensions. — Length Height Width L.V. 0.59 0.30 0.11 Material, — Approximately 400 live and 200 dead individuals. Diagnosis. — Leptocythere of medium size with notable increase in strength of ornament and in size southwards throughout its range. Ornament varying from smooth to feebly punctate with highly variable ribs. Shell not strongly calcified. Hinge with antero-median and postero-median elevated areas in the left valve of which only the former is reflected in the right valve. This species occurs as two distinct types, a “southern” form which is larger and ornamented with punctae (which increase in strength south- wards) and a smaller, smoother “northern” form. These two clinal populations do not overlap and in no locality are they found occurring together. The penis of the males from each group is identical. This species increases in size southwards as illutrated below by the follow- ing selected dimensions: Lat. 42°25’S. (Bird Island) Length Height Smooth form Range Mean Range Mean 5 & Carapaces 0.54-0.55 0.54 0.26-0.29 0.27 5 Q@ Carapaces 0.49-0.54 0.515 0.28-0.30 0.29 Lat. 47°45'10”S. (Puerto Deseado) Feebly punctate form 3 ¢ Carapaces 0.58-0.59 0.58 0.29-0.30 0.30 3 92 Carapaces 0.55-0.57 0.55 0.31 0.31 Lat. 52°45’S. (Cabeza del Mar) More strongly punctate form 3 6 Carapaces 0.58-0.60 0.59 0.29-0.31 0.30 3 @ Carapaces 0.58-0.59 0.58 0.31-0.32 0.32 This increase in size southwards is demonstrated by many other euryther- mal Cytheracea in this study and is ascribed to the fact that in the colder ARGENTINE LEPTOCYTHERIDAE 513 waters of the south, species achieve maturity more slowly and as a consequence are able to grow larger. This species is somewhat reminiscent of L. pellucida (Baird), but differs in shape and size. It is larger, less strongly, and less regu- larly pitted than L. 2. sp. A, and from L. patagonica, it differs in its more elongate shape, much less strongly calcified shell, in lacking strong ornament, and hinge structures similar to those of Callistocythere. Ontogeny. — Juveniles are only rarely encountered, probably due to the fragile nature of the shell. The following dimensions are from Cabeza del Mar: Length Height -1 Carapace 0.49 0.26 —2 Carapace 0.42 0.25 -3 Carapace 0.38 0.24 Ecology and distribution. — This is essentially a “southern” littoral species which has not been recorded from the continental shelf. It is recorded from the following littoral localities: a) Smooth form b) Punctate form Arroyo Jabali (live) Bahia Solano (live) Bird Island (live) Puerto Deseado (live) Punta Delgada (live) Cabeza del Mar (live) The difference between the two forms of the species is emphasized by the disjunct nature of their distribution, in that between the southernmost occur- rence of the smooth form, (Punta Delgada 42°47’S.) and the northernmost occurrence of the punctate form (Bahia Solano 45°42’S.), the species seems to be absent. The smooth form appears to be restricted to algae in the eulittoral zone whilst the punctate form, although essentially similar in its habit, has also been recovered from eulittoral and sublittoral sediment samples at Puerto Deseado. Leptocythere sp. Pl. J, fig. 12 Material. — Seven valves. Remarks. — Because of the small number of specimens and because of their poor state of preservation, and because the species is probably only represented by juveniles, the taxonomic position of this form is uncertain. It may represent a new species of Leptocythere because the authors do not know of another species characterized by almost equally rounded end margins and by a smooth to weakly wrinkled shell surface. Because the hinge and inner lamella are only very feebly developed, it is thought that all the specimens are juveniles. Dimensions. — Length Height R.V. Playa Grande, Mar del Plata. 0.58 0.31 L.V. Austral/VI/14. 0.55 0.30 Distribution and ecology.— With the single exception of one valve from the sediment of a eulittoral rock pool from Playa Grande, Mar del Plata, this 514 R. C. WuHaTLey anv A. MoGutmLevsky species is restricted to sediment samples, of medium to fine sand from the continental shelf between latitudes 36°12’40”S. and 39°32’S. and at depths ranging from 40 to 135 feet. Genus CALLISTOCYTHERE Ruggeri, 1953 Callistocythere dispersocostata Hartmann, 1962 Plate I, figs. 13-15 1962. Callistocythere dispersocostata Hartmann: in Hartmann-Schroeder, Mitt. Zool. Mus., Hamburg, Ergans., 60, pp. 195-198, text-figs., 52-58. Remarks.— This species, which is evidently closely related to Callisto- cythere ornata Hartmann) 1956, differs from all other species of the genus herein described in being more rounded antero-ventrally and mid-ventrally concave; in its irregularly ribbed and lobed and tuberculate ornament. In these features, and in its internal shell structure, it more closely resembles C. littoralis (Miller, 1894), the type of the genus. Material. — Approximately 2,500 specimens of which about 1,000 contain appendages. Distribution and ecology.—Wartmann (1962) originally described this species from eulittoral environments from the Pacific coast of northern and central Chile and also from Golfo Nuevo, Province of Chubut, in Argentine Patagonia. In the present study the species is almost ubiquitously encountered, often in great abundance, in littoral samples between 40°S. and 54°50’S. Whilst it has not been encountered in samples from the continental shelf, one single female valve was recovered from a sample in the mouth of the River Plate at 36°15'05”S. This latter record is thought to be an exotic one due to post- mortem transport by floating algae such as Macrocystis. This species is recorded from the following localities: Rio de La Plata/64+ (dead) Bahia Solano (live) Punta Ramirez (live) Caleta Olivia (dead) Arroyo Jabali (dead) Puerto Deseado (live) San Antonio Oeste (live) San Julian (live) Las Crutas (live) Monte Leon (dead) Bird Island (live) Rio Gallegos (live) Punta Norte (live) Puerto Porvenir (live) Caleta Valdez (live) Estancia Viamonte (live) Punta Delgada (live) Ushuaia (live) Punta Ameghino (live) In common with most of the Argentine Leptocytheridae this species is principally phytal in habit and in many localities it occurs live in some abun- dance on algae from eulittoral rock pools whilst from adjacent sedimentary environments it is only encountered as dead valves. However, this species in such localities as Caleta Valdez and Rio Gallego is found living in muddy sediments and also from within the Ria at Puerto Deseado it may be en- countered, probably living interstitially, in coarse sand and shell gravel en- vironments in both the lower eulittoral and the sublittoral. ARGENTINE LEPTOCYTHERIDAE 515 Dimensions (Puerto Deseado).— Length Height ® LV MLP 11753/a 0.50 0.29 &@ LV MLP 11753/b 0.47 0.25 g@ Carapace MLP 11753/c 0.49 0.255 @ Carapace MLP 11753/d 0.495 0.29 —1 Carapace MLP 11753/e 0.39 0.23 —2 Carapace MLP 11753/f 0.36 0.21 —3 Carapace MLP 11753/g 0.33 0.20 This material is somewhat shorter than the type material from Bahia Con- cepcion, Chile, (¢ 0.49, 0.26; @ 0.50-0.53, 0.27), but the females are higher. Callistocythere, n. sp. A Plate I, figs. 16-18; Plate II, figs. 1-3; Plate II, figs. 16-19, 22 Dimensions. — Length Height Width Ve 0.38 0.21 0.09 Material. — Approximately 3000 live, dead and fossil specimens. Diagnosis. — A new species of Callistocythere characterized by its orna- ment of large reticulae produced by the interaction of vertical and horizontal ribs, of which the vertical component is dominant dorsally and the horizontal component ventrally; by its possession of a strongly arched dorsal margin. Remarks.— This species is smaller, more acuminate posteriorly and has a more regularly ribbed ornament than C. dispersocostata Hartmann, 1962. It also lacks the large lobes and tubercules which characterize the latter species. Also, although their ranges overlap in the limited area between about 40° and 42°S, the present species is a more northern form. C., n. sp. A differs from both C. ornata (Hartmann, 1956) from the Brazilian Coast, and from C., n. sp. C in its possession of an ornament of ribs rather than small reticulae. It differs principally from C., n. sp. B in its much stronger ornament but is also longer, higher, more arched dorsally and has a more pronounced anterior cardinal angle. The present species is very close to C. litoralensis (Rossi de Garcia, 1966) from the Argentine Miocene but has a closer network of more delicate ribs and also differs in outline. It is thought, however, that this similarity is due to an ancestral relationship. Distribution and Ecology.— This species is an abundant and often domi- nant member of the ostracode faunas of marine and brackish-water environ- ments of the late Pleistocene and Holocene age in the northeastern coastal regions of the Province of Buenos Aires. Its known present day distribution is as follows: a) Littoral b) Estuary of the River Plate Santa Elena (dead) and Continental Shelf Playa Grande (dead) Rio de La Plata/59 (dead) Pocitos (live) Rio de La Plata/64 (dead) Punta Ramirez (live) Pesqueria/V/26 (dead) Arroyo Jabali (live) Almirante Saldanha/1245 (dead) Las Grutas (live) Austral/VI/8 (live) Bird Island (live) Austral/VI/13 (dead) Austral/VI/21 (dead) 516 R. C. WuHaTLey AND A. MoGuILEVsKy This species does not appear to extend in the littoral] farther south than 42°S. It is notable for the fact that in the littoral it is quite catholic in its choice of substrates, being found almost as commonly in coarse sand and silt as it is on algae. It is evidently less phytal in habit than other Argentine species of the genus, with the exception of C., n. sp. B. It is also, with the exception of a new genus and species, the most commonly encountered member of the family on the Continental Shelf. C.,n. sp. A and C., n. sp. B are probably mutually exclusive, since they only occur together in one sample (Rio de La Plata/64), and here the former species is only represented by a single specimen. The authors hope to better understand this relationship when they have investigated more samples from the estuary of the Rio de La Plata and from the Uraguayan and Brazilian coasts. Callistocythere, n. sp. B Plate II, figs. 45 Material. — Fifty-eight dead valves and carapaces, all adults. Dimensions. — Length Height Width Female left valve 0.40 0.235 0.09 Diagnosis.— A species of Callistocythere characterized by its small to very small size; cardinal angle rounded in right but pronounced in left valves; ornament of dorso-lateral irregular ribs and ventro-lateral longitudinal ribs between which is an irregular smooth area, anterior terminal hinge ele- ment of the right valve distinctly lobate. Remarks.— This species differs from C., n. sp. A in its smaller size, straighter dorsal margin, less pronounced cardinal angles, and in possessing a smooth central unornamented area. Present evidence suggests that they are almost mutually exclusive as in only one sample (Rio de La Plata/64) do they occur together and in this, C., n. sp. A is represented by one specimen only. The present species differs from all other species of the genus known to the authors in possessing the smooth unornamented central area and the strongly lobed anterior terminal element in the right valve. Ecology and Distribution.— This species has only been recovered from three samples and in all cases is represented by dead adults. A single female left valve was recovered from sample Austral/VI/23 at a depth of 40 feet in fine sand and the remainder of the material is from samples Rio de La Plata 61 and 64 which are from fine muddy silt at depths of 31/4 and 21/4 Fm respectively. The known geographical range of the species is between 36°12’S. and 39°20’S. although the authors expect to encounter it in samples, yet to be picked from off the coasts of Uruguay and southern Brazil. Callistocythere, n. sp. C Plate II, figs. 6-9; Plate III, figs. 23-25, 28 Dimensions. — Length Height Width EW 0.425 0.24 0.09 ARGENTINE LEPTOCYTHERIDAE 517 Material. — Thirty-three 2 specimens of which seven were dead. Diagnosis. — Callistocythere characterized by shape and outline similar to Leptocythere but with hinge and another internal features typical of the genus. Ornament of irregular ribs, reticulae and tubercules, differently ex- pressed in the two valves. Remarks.— This species exhibits characteristics which place it between Leptocythere and Callistocythere; the ornament of ribs, reticulations and tuber- cules, the hinge and rather asymmetrical marginal pore canals are characteris- tics of the latter, whereas the very feebly developed ventral locking device, general shape, and outline are more characteristic of the former genus. It is, however, evidently very similar to Callistocythere costata (Hartmann, 1956) from Brasil. It differs however, in being more distinctly sulcate medianly and in possessing two vertical ribs which bound this sulcus anteriorly and posterior- ly and a median longitudinal rib which bounds it ventrally. The present species also differs in being deeply sulcate postero-ventrally. Distribution and ecology.— This species has only been found in the lit- toral where it occurs along the coast of the southern part of the Province of Buenos Aires, that of Rio Negro and also part of Chubut, approximately be- tween latitudes 40°30’S and 43°S. It occurs in the following localities: Punta Ramirez (live) Arroyo Jabali (live) Las Grutas (dead) Punta Delgada (live) Although recorded from Arroyo Jabali in medium to fine sand and silt, this species is most commonly phytal in habit, being particularly associated with the genera Ulva, Enteromorpha, Ceramium, and Polysiphonia. The authors are unable to account for the absence of males of this species throughout its distribution except perhaps by suggesting some different ecological requirements for the two sexes. All the females were recovered from eulittoral samples and it is possible that the males may be sublittoral in habit and could thus not be represented in this study which contains much fewer sublittoral than eulittoral samples. This would be aggravated by the fact that in no part of its range is the species of common occurrence. Family CYTHERIDEIDAE Sars, 1925 Subfamily NEOCYTHERIDEIDINAE Puri, 1957 New genus and species Plate II, figs. 12-18; Plate III, figs. 29 Remarks. — The present material contains only two live specimens and in these the appendages are too poorly preserved to describe. The authors are cur- rently attempting to obtain living material of this spcies in order to describe the soft parts of the adult. 518 R. C. WuaTLey anv A. MoGulILevsky Dimensions. — Length Height Width Holotype from Ilha Bela, Brazil. 0.41 0.26 0.07 Adult & RV (Sample SA/5) 0.515 0.21 0.10 $ Carapace (Sample Austral/VI/13) 0.53 0.215 0.19 g RV (Sample Rio de La Plata/64+) MLP 11760/c 0.53 0.21 0.11 @ Carapace (Sample West Wind/95) 0.57 0.27 0.25 @ RV (Sample Rio de La Plata/61) MLP 11760/e 0.52 0.26 0.12 @ Carapace (Sample Austral/VI/10) 0.58 0.265 0.245 -1 Instar. RV (Sample Rio de la Plata/61) 0.45 0.20 RV (ditto) 0.46 0.20 LV (Sample A/VI/—) 0.48 0.21 LV (ditto) 0.48 0.21 —2 Instar. RV (Sample Austral/VI/6) MLP 11760/f 0.41 0.18 LV (Sample Rio de La Plata/59) 0.40 0.19 The males are more elongate and more pointed posteriorly than the females and they are also, both actually and proportionally less high. The left valve is substantially larger than the right with strong ventral and postero- dorsal overlap. The surface of the shell, as can be seen in the illustrations, is intricately covered with small tubercles along the line of the ribs. Eye spot a small clear non-elevated patch. Normal pores very small and apparently open. Inner lamella wide, particularly anteriorly where there is a crescentic vestibule. A smaller vestibule also occurs posteriorly. Marginal (radial) pore canals few, long and slender; there are 8-10 anteriorly of which at least two bifur- cate medially, the resulting rami of which may terminate as false canals. Be- tween eight and ten canals which always occur as parallel pairs, occur pos- teriorly and postero-ventrally. Hinge lophodont. In the right valve the terminal elements are low smooth elevations, connected by a long smooth groove which is slightly widened at its distal extremities. The smooth terminal sockets in the left valve are very weak and are open to the anterior and interior. The adductors comprise an oblique line of four small scars, anterior to the most dorsal of which is a large heart-shaped scar, there is also a strongly incised fulcral pit. Distribution and ecology.—In the present study this species has been re- corded in sediments of the continental shelf with a lesser number of records from the littoral: Littoral Continental Shelf Playa Grande (dead) Almirante Saldanha/1252 (dead) Punta Ramirez (dead) Rio de La Plata/59 (dead) Las Grutas (dead) Rio de La Plata/61 (dead) Pesqueria V/26 (dead) Rio de La Plata/64 (dead) Almirante Saldanha/1245 (dead) Austral/VI/6 (dead) Austral/VI/13 (dead) Austral/VI/3 (dead) Austral/VI/10 (dead) Austral/VI/15 (dead) Austral/VI/23 (dead) West Wind/95 (live) ARGENTINE LEPTOCYTHERIDAE 519 This species is evidently “northern” in character, ranging at least as far north as 23°45’S., and in the littoral as far south as 40°40’S., and on the shelf to 42°23’S. DISCUSSION It is notable that in Argentine waters, Leptocythere and Callistocythere in respect of the majority of the species encountered, are more phytal] in their habit than those in other areas. Although species of the two genera are some- times found in association with algae and marine angiosperms, this is usually in the form of “accidental” occurrences, by voluntary or involuntary migration from closely adjacent populations living on or within sediments. European species are usually found, both in marine and brackish environments, living on the surface, interstitially, or burrowing within the sediments. From all the various littoral stations collected in this work, samples of both sediments and algae have been taken. In some areas, such as Pocitos, Punta Ramirez, Arroyo Jabali, Caleta Valdez, and Puerto Deaseado, Leptocytheridae have been re- covered live from fine-grained sediments. These areas are all relatively sheltered and it is thought to be this factor which allows Leftocythere and Callistocythere to inhabit sedimentary environments in these cases. However, in these stations, where there are closely adjacent phytal environments, these latter always contain a much greater density of ostracodes (not only Lepto- cytheridae) than do the sediments. On the exposed rocky beaches and head- lands along the coast, sediment samples from all parts of the littoral and sub- littoral have, even from the bottom of deep and well-protected rock pools, failed to yield live Ostracoda. At the same stations, members of the Lepto- cytheridae occur almost ubiquitously, and frequently in substantia] abundance in samples of algae. This phenonmenon is not confined to the family under consideration. Of the 160 species isolated to date in the study we are undertaking on the Argen- tine benthonic Ostracoda, some 80% are restricted to the littoral, where, with the exception of such localities as mentioned above, there is an almost 100% dependence upon algae. Many other genera, such as Argilloccia, Macrocypris, Paracypris, and the majority of the Hemicytheridae, not normally considered as phytal species, are found on algae, in association with such well-known phytal forms as Parakrithella, Xestoleberis, Paradoxostomatidae. The authors, whilst realizing that this extreme dependence upon algae is undoubtedly a function of the interaction of many factors, consider that exposure is the primary cause, despite the fact that along the southern coasts of South America, westerly winds prevail. Text-figure 1 gives the geographical distribution of the various species in both the littoral and the shelf. Whilst it is obvious that the area of Penin- sula Valdez delimits the maximum northward extent of many “southern” forms, and vice versa, the authors prefer to delay the discussion of the disposition 520 R. C. WHaTLeEy AND A. MocGulILEvskKy of ostracode faunal provinces along the Argentine coast, until they are able to publish their findings from the total fauna. REFERENCES Boltovskoy, E. 1964. Provincias zoogceograficas de América del Sur y su sector antdrtica segtin los foraminiferos benténices. Boln. Inst. Biol. mar., Mar del Plata, 7, pp. 93-98. Brady, G. S., and Norman, A. M. 1889. 4 monograph of the marine and freshwater Ostracoda of the North Atlantic and of north western Europe. Section 1. Podocopa. Scient. Trans. R. Dubl. Soc. N.S. 4 (2), pp. 63-270. Hanai, T. 1957. Studies on the Ostracoda from Japan. I Subfamily Leptocytherinae, new subfamily. Fac. Sci. Tokyo Univ. Jour., Sec. 2., 10 (3), pp. 431-468. Hartmann, G. 1956. Weitere neue marine Ostracoden aus Brasilien. In E. Titchak and K. H. W. Koepeke, Beit. neotrop., Gustav Fischer Verlag., pp. 19-62. 1961. Beitrag zur Ontogenie des Ostracodenschlossen (mit Beschreibung von 2 neuen Arten). Z. W. Z., 165, pp. 428-452. Hartmann-Schréder, G., and Hartmann, G. 1962. Zur Kenntnis des Eulitorals der chilenischen Pazifikkiiste und der argentinischen Kiiste Stidpatagoniens unter besondered Beritck- sichtigung der Polychaeten und Ostracoden. Mitteil. Hamburg. Zool. Mus. Inst., Erganzungsband zu Band, 60, pp. 1-270. Kingma, J. T. 1948. Contributions to the knowledge of the Young-Cenozoic Ostracoda from the Malayan Region. Thesis Univ. Utrecht, 119 pp. Rossi de Garcia, E. 1966. Contribucién al conocimiento de los Ostrdcodes de la Argentina. I Formacién Entre Rios, de Victoria, Provincia de Entre Rios. Rev. Asoc. Geol. Argentinea, 21, (3), pp. 194-208. Sars, G. O. 1922-1928. An account of the Crustacea of Norway. Bergen Museum, 9, pp. 1-277. Van Morkhoven, F. P. C. M. 1963. Post-Palaeozoic Ostracoda. Their morphology, taxonomy, and economic use, vols. I, II, Elsevier, Amsterdam, pp. Wall, D. R. 1969. The taxonomy and ecology of Recent and Quaternary Ostracoda from the southern Irish Sea, Unpublished Ph.D. thesis, University of Wales. Whatley, R. C. and Wall, D. R. 1969. A preliminary account of the ecology and distribution of Recent Ostracoda in the southern Irish Sea. In Neale, J. W. (ed). The Taxonomy, Morphology and Ecology of Recent Ostracoda. Olive1 and Boyd, Edinburgh, pp. 268-298. ARGENTINE LEPTOCYTHERIDAE 521 Whatley, R. C., Whittaker, J. E., and Wall, D. R. 1971. A taxonomic note on the genus Leptocythere Sars with particular reference to the type species. Bull. Centre Rech. Pau-SNPA, 5 suppl. pp. 399-408. R. C. Whatley, A. Moguilevsky, Division Micropaleontologia, Depto. Biologia, Facultad de Ciencias Naturales y Museo, Facultad de Ciencias Universidad Nacional de La Plata, Exactas y Naturales, Paseo de Bosque, Universidad de Buenos Aires, La Plata, Argentina Ciudad Universitaria, and Pabellon 2, Pise 4, Nunez, Department of Geology, Capital Federal, University College of Wales, Argentina Aberystwyth, Wales DISCUSSION Dr. G. Hartmann: You mentioned my species Neocytherideis marchilensis archi- lensis (it’s wrong to place it in Cushmanidea). Did you see the marginal zone, and are you sure that it is not Mesocythere foveata? Dr. Whatley: The ventral and posterior part consists of unbranched pore canals which occur in pairs. Dr. Sandberg has beautiful illustrations of this feature. Another interesting feature of this form is that it has a very deeply incised crescentic fucral furrow and fucral hole, but in some it is concentric very reminiscent of this other animal. Dr. Hartmann: Did you have the soft parts? Dr. Whatley: No, we had semi-mummified soft parts of these. I haven’t found them living. 522 Figure 1-3. 46. 7-11. 12. 13-15. 16-18. R. C. WuaTLey anp A. MoGuiILEvsKy DESCRIPTION OF PLATE [ Leptocythere patagonica Hartmann, 1962 1. 9 L.V. MLP. 11745/a. External view; X 46.6. 2. -1 Instar. R.V. MLP. 11745/d. External view; X 46.6. 3. 6 R.V. MLP. 11745/c. External view; x 46.6. Leptocythere, n. sp. A 4. 6 L.V. MLP. 11746. External view; x 60. 5. 9 R.V. MLP. 11747/a. External view; x 60. 6. 6 L.V. MLP. 11746. Detail of anteromedian normal pore canal and seta; x 2000. Leptocythere, n. sp. B 7. 9 L.V. MLP. 11749/a. Detail of the extreme antero- median part of the shell; x 333. 8. ¢ R.V. MLP. 11748. External view; X 63.3. 9. 9 L.V. MLP. 11749/a. External view; X 63.3. 10. ¢@ L.V. MLP. 11748. External view; x 63.3. 11. ¢ R.V. MLP. 11748. Detail of anterior; x 167. Leptocythere sp. 12. L.V. MLP. 11750. External view; X 46.6. Callistocythere dispersocostata Hartmann, 1962 13. 9 L.V. MLP. 11753/a. External view; X 60. 14. 6 R.V. MLP. 11753/b. External view; X 60. 15. @ R.V. MLP. 11753/b. Detail of posterior; X 167. Callistocythere, n. sp. A 16. @ L.V. MLP. 11745. External view; x 83.3. 17. 9 Carapace. MLP. 11755/g. External view; X 83.3. 18. ¢ R.V. MLP. 11754 External view; X 83.3. ARGENTINA LEPTOCYTHERIDAE Plate I 524 Figure 1-3. 4, 5. 6-9. £0;,11. 12-18. R. C. WuaTLey anp A. MoculILevsky DESCRIPTION OF PLATE II Callistocythere, n. sp. A 1. ¢@ R.V. MLP. 11759. Detail of normal pore canal; X 2666. 2. o L.V. MLP. 11759. Detail of posterior; X 266. 3. g R.V. MLP. 11759. Detail of anterior; X 266. Callistocythere, n. sp. B 4. 9 L.V. MLP. 11756. External view; X 76.6. 5. & Carapace. MLP. 11757/f. Right lateral view; X 76.6. Callistocythere, n. sp. C 6. 2 R.V. MLP. 11758. Detail of pore canal and seta; X 2333. 7. 9 L.V. MLP. 11758. External view; X 66.6. 8. Q R.V. MLP. 11758. External view; xX 66.6. 9. Q Carapace. MLP. 11759/a. External view; X 66.6. Callistocythere litoralensis (Rossi de Garcia, 1966) 10. Q R.V. External view. MLP. 11761/a. x 83.3. 11. ¢ L.V. External view. MLP. 11761/b. X 83.3. New genus and species 12. ¢ R.V. MLP. 11760/c. External view; X 60. 13. ¢ R.V. MLP. 11760/c. Detail of anterior; X 167. 14. -2 Instar. L.V. MLP. 11760/f. External view; X 73.3. 15. -2 Instar. L.V. MLP 11760/f. Detail of posterior; X 260. 16. 92 Carapace. MLP. 11760/e. External view; X 53.3. 17. 2 Carapace. MLP. 11760/e. Detail of anterior; X 167. 18. Q Carapace. MLP. 11760/e. Detail of anterior; X 1666. Plate II ARGENTINA LEPTOCYTHERIDAE 525 526 Figure 1-7. 8-15, 20. 16-19, 22. 21. 23-25, 28. 26, 27. 29. R. C. WuaTLey anp A. MocuILevsky DESCRIPTION OF PLATE III Leptocythere, n. sp. A 1. Holotype, ¢ MLP. 11746. Penis. Right inner lateral view; x 128. 2. Paratype. ¢ MLP. 11747/s. Second thoracic leg. Left outer lateral view; X 128. 3. Paratype. 9 MLP. 11747/b. First thoracic leg. Right outer lateral view; X 128. 4. Holotype. ¢ MLP. 11746. First antenna. Right inner lateral view; X 128. 5. Paratype. 6 MLP. 11747/s. Mandibles. Anterior view; X 128. 6. Topotype. 2 L.V. Detail of anterior marginal area in trans- mitted light; x 71.5. 7. Holotype. 6 MLP. 11746. Second antenna. Right inner lateral view; X 128. Leptocythere, n. sp. B 8. Holotype. ¢ MLP. 11748. Penis. Right outer lateral view; < 3300 and 6600 (Ref. 71550/22 and /18). The “chitinous” external pellicle has become very thin, clearly revealing the hillocks of under- lying crystailites; in certain places (left part of fig. 4), the pellicle has completely disappeared. Note the crystals of neoformation (fig. 3 — see also Plate 8). 5,6. Cytheridea variepunctata Oertli, 1956. Well (fig. 5) and poorly (fig. 6) conserved specimens. Rupelian, Delémont (Canton of Berne, Switzerland). X 1530 (Ref. 70553/16 and /17). “Cortex” of tightly packed grains, nearly aligned in the external layer (fig. 5), practically entirely missing in the specimen on the right (fig. 6). 564 Figure H. J. Ort EXPLANATION OF PLATE 5 External layer (“cortex’”’) (see also Plates 3 and 4). 1,2. Cytheridea sp. Well-conserved specimen. Paleocene, Cerisols (Dept. Ariége, France); X 126 and xX 1260 (Ref. 69140/8 and /22). Resistance of the external layer (see also Plate 4, fig. 1). The anteromedian area of the specimen shown here has been placed for 1 minute in an HCI solution. Fig. 1: before attack; Fig. 2: central area of the picture after attack. The acid has created a cavity, revealing the angular to rounded crystallites of the interior of the test. The “chitinous” external layer is visible to the left, and even more so to the right, where it overhangs. 3,4. Hermanites sp. Well conserved specimen. Same stratum; X 820 and X 3850 (Ref. 69136/7 and /12). Detail of the surface, with cavity due to the artificial removal of a spine. Fig. 4 shows — at a slightly different angle — the left part of the cavity (angular crystallites, loosely arranged; external layer of small, subrounded grains in a compact layer). 5. Cytherella cf. ovata (Roemer, 1841). Poorly conserved specimen. Albian; Gargas-Apt section (Dept. Vaucluse, France). X 2820 (Ref. 70559/18). 6-8. Cytheridea variepunctata Oertli, 1956. Poorly conserved specimen. Rupelian, Delémont (Canton of Berne, Switzerland) ; X 385, 770 and 3850 (Ref. 70553/18, /20, /23). In these two species, the external layer has practically disappeared. In fig. 5, the crystallites towards the exterior still show good cohesion; in fig. 8, they are beginning to separate. 565 CONSERVATION OsTRACODE TESTS 5 Plate Plate 6 . J. OERTLI H 566 CONSERVATION OsTRACODE TESTS 567 EXPLANATION OF PLATE 6 Observations on the marginal zone. Figure 1-4. Falunia ? sp. Well-conserved specimen. Subrecent; W Kiskalesi, Icel (Turkey) ; xX 1200, 2850, 550 and 1260 (Ref. 71536/23 and /24; 71531/18; 71536/25). In Figures 1 and 2 (anterior marginal zone), the thin inner lamella can be clearly distinguished from the outer lamella; its formation and chalky appearance are much like the “cortex” of the external layer (clearly visible in the centre of Figure 2). In Figures 3 and 4 (ventral marginal zone), the inner lamella lies side by side with the outer lamella. Note its internal structure (perpendicular arrangement of the crystallites — see especially fig. 4) and the flap of the external layer (on the right of fig. 4). 5-7. Schuleridea perforata (Roemer, 1838). Poorly conserved specimen. Lutetian; Villiers-St.-Frédéric (Dept. Yvelines, France); X 165, X 375 and X 1650 (Ref. 70547/23, /22 and /27). The inner lamella is very compact and can be clearly distinguished from the outer lamella. 8,10. Echinocythereis sp. Well-conserved specimen. Subrecent; N Atlantic (64°45’N, 29°06’W; 568 fathoms); & 750 and xX 550 (Ref. 71531/12 and /13). The inner lamella is closely linked to the outer lamella, but still has a == perpendicular structure, intersected here by secondary (chitinous ?) jamellae which penetrate fairly deeply into the interior; these lamellae form the septa on the surface. 9. Cytheretta sp. Well-conserved specimen. Lutetian; Villiers-St.-Frédéric (Dept. Yvelines, France); X 285 (Ref. 71077/27). Contact inner/outer lamella. 568 Figure iL: 4, 5. Fyfe OERrer EXPLANATION OF PLATE 7 Special arrangements of the crystallites Echinocythereis sp. Well-conserved specimen (section through a spine). Subrecent; N Atlantic (64°45’N, 29°06’W; 568 fathoms). X 565 (Ref. 71531/16). Hermanites sp. Poorly conserved specimen (section through a crest; the external surface is below). Paleocene, Cerisols (Dept. Ariége, France) ; xX 3600 (Ref. 69143/9). In the ribs, nodules, knobs, spines, the ar- rangement of the crystallites is subparallel to the surface; the “movement” begins well below the jagged formations (see top of fig. J) Loxoconcha sp. Well-conserved specimen. Subrecent; W Kiskalesi, Ice] (Turkey) ; X 1320 (Ref. 71536/34). Lateral pore canal (sieve form) running through the test without affecting the arrangement of the crystallites (outside edge: towards the bottom). Bradleya sp. Fairly well-conserved specimen. Subrecent; Persian Gulf; « 1420 and X 1200 (Ref. 71550/43 and 71577/6). Lateral pore canal (sieve form) running through the test, having a marked effect on the arrangement of the crystallites (‘‘diapir”). Outside edge, towards the bottom (opening blocked by “chitinous” material) in fig. 4, towards the top in fig. 5. — Note the laminar arrangement of the crystallites and the canal’s coating of organic matter partially conserved. Fastigatocythere fullonica (Jones, 1884). Well-conserved specimen. Upper Bathonian, Boulogne s/Mer (Dept. Pas-de-Calais, France) ; X 685 (Ref. 71550/3). Same feature: lateral pore canal in “diapir’ form (outside towards the left). CONSERVATION OsTRACODE TESTs Plate 7 Plate 8 ¢ TU. i ‘Gis, se * fe \\ Elga}psOQERTET Figure 3, 4. 5-8. CONSERVATION OsTRACODE TESTS 571 EXPLANATION OF PLATE 8 Recrystallizations and fillings (see also Plate 9). Hermanites sp. Poorly conserved specimen. Paleocene, Cerisols (Dépt. Ariége, France); X 355 (Ref. 69144/10). Fastigatocythere fullonica (Jones, 1884). Moderately well conserved specimen. Upper Bathonian, Boulogne s/Mer (Dept. Pas-de-Calais, France); X 1320 (Ref. 71550/21). Partial recrystallization of the test (see also Plate 2, fig. 6 and Plate 4, fig. 2). Bythocypris ? sp. Pyritised specimen, not very well conserved. Paleocene; bore-hole in Libya; X 1425 and & 7100 (Ref. 71515/4 and /5). Recrystalliza- tion by pyritisation. Note that in spite of the “metamorphosis”, the “chitinous” external layer has remained intact in places (see also Piates2. tic Sand Plate 9) figs 2) Bythocypris ? sp. Poorly conserved specimen. Paleocene; bore-hole in Libya; x 67, x 340, X 1370 and x 685 (Ref. 71506/38; /41; /40 and /43). The test has been almost entirely destroyed by the crystallization (marcasite ?). Views of the surface (fig. 5: whole specimen; fig. 6: rear area; fig. 7: central area; fig. 8: medio-ventral area). 5v2 H. J. OertTui EXPLANATION OF PLATE 9 Figure 1-3. Bythocypris ? sp. Pyritised specimen. Paleocene; bore-hole in Libya; x 1260, X 137, x 840 (Ref. 71506/26, /29, /32). Crystallized internal cast. In certain places, recrystallization does not attack, or only slightly the test itself (fig. 1), in others, the crystals reach and pass through the surface (figs. 2, 3; see also Plate 8). 4,5. Bythocypris ? sp. Moderately well conserved specimen. Tertiary, Iran; xX 55 and X 275 (Ref. 70550/20 and 70550/21). The test has been partially re- moved, thereby revealing, in the centre, crystals of gypsum; how- ever, this crystallization has not attacked, strictly speaking, the test. 6,7. Fabanella cf. boloniensis (Jones, 1882). Fairly well conserved specimen. “Infravalanginian” near Brouco, Lisbon region (Portugal) ; X 1200 and 600 (Ref. 71577/51 and /52). In this case, too, the filling of the carapace has not affected the structure of the wall. Plate 9 CoNSERVATION OsTRACODE TEsTs 573 H. J. OertT1i Figure it 2: 3, 4. 5, 6. 7, 8. LO, 11. CONSERVATION OsTRACODE TESTS 575 EXPLANATION OF PLATE 10 Transparency — opacity. Lustre — dullness. Falunia ? sp. Transparent and opaque specimens. Subrecent; W Kiskalesi, Icel (Turkey) ; & 3300 (Ref. 71536/26 and /30). Apparently, the inter- nal structure of both forms is the same. Same specimen as fig. 1, before fracturing, external view; X 55 and x 550 (Ref. 71517/35 and /36). Same specimen as fig. 2, before fracturing, external view; X 55 and « 550 (Ref. 71517/37 and /38). There seems to be some evidence that the shape of the surface is responsible for the degree of trans- parency. Bradleya sp. Surface of transparent (7) and opaque (8) specimens. Subrecent, Persian Gulf; < 2830 (Ref. 71577/11 and /9). Comparison of these two photographs would seem to confirm the important role played by the surface. Schuleridea perforata (Roemer, 1838). Translucent specimen. Lutetian; Villiers-St.-Frédéric (Dept. Yve- lines, France); 770 (Ref. 70547/13). The very inhomogeneous internal structure of the test does not detract in any way from its perfect transparency! Fabanella cf. boloniensis (Jones, 1882). Surface of opaque specimens, glossy (10) and dull (11); “Infra- valanginian”, Brouco, Lisbon region (Portugal); X 1200 (Ref. 71577/19 and /17). Very striking differences in the fine morphology of the surface. APPLICATION OF THE ELECTRON MICROPROBE ANALYZE RSTO Tit srUDY OF THE OsRACODE GARAPACE H. Meape Capot, Rocer L. KAESLER, AND W. R. vAN SCHMUS University of Kansas ABSTRACT Preliminary electron microprobe analysis of specimens of Holocene marine Ostracoda suggests that variation in concentration of MgCOs in calcite of the carapace varies markedly from the outside to the inside of the carapace of individuals in some taxa and remains relatively constant in others. Super- imposed on this individual and phylogenetic variation is a tendency to secrete calcite with less magnesium in cold water than in warm water. Because of early diagenesis, electron microprobe analysis is not suggested for study of fossil or subfossil specimens until the effects of diagenesis are more thoroughly understood. APPLICATION DEM ANALYSEUR MICROPROBE ELECTRONIQUE A L’ETUDE DE LA CARAPACE OSTRACODE RESUME L’analyse préliminaire, par le microprobe électronique, des spécimens Holo- cene Ostracoda marin, suggére que la variation dans la concentration de Mg CO; dans le calcite de la carapace, differe d’une maniere marquante de lextérieur a ]’intérieur de la carapace des spécimens individuels des taxa, et cette variation reste relativement constante dans d'autres spécimens. I] y a une tendence a sécréter le calcite avec moins de magnésium dans l’eau chaude, qui est superposée sur cette variation individuelle et phylogénique. A cause de la diagénése hative, l’analyse microprobe électronique est a déconseiller pour l'étude des spécimens des fossiles ou des sous-fossiles jusqu’a ce que les effets de la diagénése soient mieux compris. INTRODUCTION The composition of calcite in the skeletons of many marine organisms has been shown to be dependent upon environment and phylogeny. Magnesium is the major ion that substitutes for calcium in calcite. In biogenic calcite, the amount of magnesium carbonate may range from nearly 0 to about 25 mole percent! Chave (1954) first examined calcite of the ostracode carapace in an X-ray diffraction study of a mixture of species from six Holocene environ- ments. He was able to show a positive correlation between water temperature and mole percent MgCOs in calcite, but because he studied mixed samples, he was not able to isolate the effects of phylogeny or taxonomic affinity. In a later study, Foster (1959) (see also Foster and Benson, 1958) was un- enthusiastic about results from X-ray diffraction studies, partly because of the small amount of material in the ostracode carapace. Since the work of Chave (1954), environmental factors that influence the substitution of magnesium for calcium have been widely discussed (Lowen- stam, 1963; Dodd, 1967), but no new data have been added to support hypo- theses about the ostracode carapace. Principal current hypotheses are that magnesium substitution in biogenic calcite is controlled largely by phylogeny, 578 H.M. Capnot, R. L. Kaeser, AnD W. R. vAN SCHMUS temperature, and rate of growth. The latter two of these are factors that are probably highly correlated with each other in many organisms. Moberly (1968) demonstrated that rate of growth may be an important factor controlling concentration of magnesium in calcite. Both algae and bivalves incorporate more magnesium into their skeletal material during times of rapid growth than during times of slow growth. Whether this applies to Ostracoda is open to question. Unlike most calcite-secreting organisms, ostracodes secrete their carapaces very rapidly following ecdysis rather than growing con- tinuously. Therefore, seasonal changes in temperature will not affect the composition of calcite within a single carapace. It does not follow, however, that Moberly’s (1968) hypothesis is incorrect — only that variations within an ostracode carapace are due to some cause other than seasonal variations. The purpose of this paper is to present preliminary results of an investiga- tion using electron microprobe analysis of the composition of calcite of the ostracode carapace (see also Cadot, et al., 1972). Specifically, we have investigated 1. distribution of magnesium within carapaces, 2. phylogenetic control of magnesium concentration by studying several individuals from the same taxon from many different environments, and 3. enviromental control, especially the effects of temperature. On the basis of electron microprobe analysis, we have reached some con- clusions, but we hasten to emphasize that they are tentative and that additional work is now underway to test these ideas. Three sources of variation in mole percent MgCO; have been identified: 1. variation within individual carapaces, 2. variation between carapaces collected from warm and cold water, and 3. variations due to phylogeny — that is, marked differences between individuals from distantly related genera from the same environment. By far the greatest variation in mole percent MgCOsy occurs within calcite of individual carapaces rather than between carapaces collected from warm and cold water. However, within a single genus, differences between specimens from different environ- ments may correlate with differences in water temperature. Finally, in order to learn about primary distribution of MgCO; in the carapace it is important to study specimens that still contain soft parts. Especially in cold water, early diagenesis of the calcite may result in a redistribution of magnesium through- out the carapace or a loss of magnesium from high magnesium calcite. METHODS OF ANALYSIS The electron microprobe analyser is an instrument somewhat akin to the scanning electron microscope in which the characteristic X-ray spectra generated by an electron beam are analyzed for wavelength and intensity. “To a first approximation, the intensity of a given characteristic X-ray line A of the K element A is proportional to the concentration of the element A in the mineral” (Keil, 1967, p. 6). Electron microprobe analysis is well suited for study of concentration of magnesium in biogenic calcite because the analysing beam can be focused to a ELECTRON MICROPROBE OSTRACODE CARAPACE 579 diameter of only a few microns. Because the electron beam can be so finely focused, it is possible to analyze the composition of calcite at several points in a traverse across the ostracode carapace. In our study, a spot size of 6 to 8 microns was used in order to minimize decomposition of the calcite being analyzed. The “probe tracks” at which calcite was analyzed are clearly visible in some of the figures in Plate 1. Moreover, because specimens are studied in polished section using X-rays, the danger of contamination from external sources is virtually eliminated. Lipps and Ribbe (1967) concluded that “analysis to planktonic foramini- feral tests using an electron microprobe is limited by the nature of the speci- mens whose thin and porous walls make reliable quantitative results difficult to obtain.” Our pilot study has shown that good data can be obtained from ostracodes with a microprobe because the calcite is dense and not porous. Our analytical error is probably less than 5 percent and is certainly less than 10 percent. Details of the operating procedure were reported by Cadot, et al. (1972). DISCUSSION Table 1 shows the number of ostracodes analyzed and the number of analyses of each species. Approximate water temperature, mean mole prcent MgCoO:, and the coefficient of variation of the analyses with 95 percent con- fidence limits are also shown. Part of this infermation is summarized graphically in Text-figure 1 in which the concentration of MgCOsz of seven ostracode valves is shown along transects from the outside to the inside of the valves. Although the results reported below are from analyses of single valves, they are generally supported by multiple analyses of other specimens of the same species from the same locality. VARIATION WITHIN CARAPACES For those specimens studied, the greatest variation in concentration of MgCO; within carapaces was found in species of Bairdia (Pl. 1, figs. 1, 2). In Text-figure 1, transects A, B, and C represent concentrations of MgCO3 in valves of three different species of Bairdia from different places. Note the tendency for a high MgCO; content in the inner portion of all three transects and in the outer part of transects A and B. Transects D, E, and F show the concentration of MgCOs; in three speci- mens of Arithe (PI. 1, fig. 3), again from three different areas. In comparison to the Bairdia species, specimens of Krithe show almost no variation in concentration of MgCO; within individual carapaces. Transect G shows the concentration of MgCOs in a specimen of Macro- cypris from the deep, cold water of the Tasman Sea. ‘Text-figures 5 and 6 of Plate 1 show the polished sections of two specimens of Macrocypris from cold water. The concentration of MgCO; shows a marked discontinuity between the low-magnesium calcite on the outside of the carapace and the high- magnesium calcite on the inside. This discontinuity may coincide with the layering of calcite in the carapace that is shown in Plate 1, figures 5 and 6. H. M. Canot, R. L. Karsier, AnD W. R. vAN ScHMUS 580 $SZ sask[Buy pom ON WOI} Ppaljipowl) Uonerea jo A onl tmnrtn ‘2adg #0 50'N $2'61=-60°8E c8'+ 088 86°61 98° Ch 06 LI EE 8h 97E =T10°SC SS PI Ef 9E 18'S = 85°01 flr +=+r'8 tO CILh El £0°S =-LO'TT 9¢°S =-LL'6 “IBA ER peck) ROU Z9'+ OnGal nevaze[q uewse 7 ‘ds ppyjasayia yy ae pr[[arayyAD vuldooAjel +7 L Ses UE[[aSEJ, JO 34S SI]VUOIPIAIUL D1IIIO [IBA L6'£ Oat! Bag UPUISE T ‘ds s1ugfo04190 J BaoeplidAy 232 Fe 2 nveoaje[q Uewse yj ‘ds Dips g $c'S OG BEpnullag ‘ds vipsivg Ts's ‘O08¢ sourddryiyd ‘ds vipsivg BIORIPIIEG 80'T qO)ay4 uR][aseyy JO 3S "ds siasaysho0uryr gq c3°0 Doe vag UPUISE | ‘ds ayy Lut ‘Dev neaje,q Uewse y, ‘ds ayj4 7 6S'T iL UR[[asePY JO 4S vynporg IY JIA (G3 TAG Ppnuwisg "ds $149q9]0]59X BIOBIIYIAD vuldooopog ®9003W ‘dwia J, Aye00T % soy uvajy S}USTOIJJIOI JO SUI] P%UapIyuod yuadIad ¢6 "(ZZ61 ‘“1a[seey pue ‘snuryd9g ueA ‘oped UYIM ‘s}[Nso1 pue pezAjeue BpoOoesysg “T %Qk L, Mole percent MgCO, Outside ——=—— Inside Text-figure 1. Mole percent MgCO; measured in transects from outside to inside surface of carapace. A. Bairdia sp., Philippines; B. Bairdia sp., Bermuda; C. Bairdia sp., Tasman Sea; D. Krithe producta, Strait of Magellan; E. Krithe sp., Tasman Plateau; F. Krithe sp.. Tasman Sea; G. Macrocypris sp., Tasman Sea. 582. H.M.Canor, R. L. KAgsier, anv W. R. vAN ScHMuS We believe that statements about the concentration of MgCOs in the ostra- code carapace must be based on a consideration of the appreciable variation and possible zonation that may be present within a carapace. Clearly the mean value of MgCOs; in transect F conveys more information that the mean con- centration in, say, transect B where the MgCOs; is bimodally distributed. We hope that work now in progress will help provide a coherent picture of the amount of variation in MgCO, likely to occur in individual carapaces. VARIATION WITH ENVIRONMENT In the specimens studied, the concentration of MgCOz; varied with tempera- ture so as to support Chave’s (1954) hypothesis. Transects D, E, and F (Text- fig. 1) represent analyses of Krithe from progressively cooler water — the Strait of Magellan, the Tasman Plateau, and the Tasman Sea respectively. With very little overlap, the specimens from warmer water have more MgCoOs in their carapaces. Among the specimens of Bairdia studied, the variation is not so straight- forward. Transects A, B, and C through specimens from progressively cooler water, the Philippines, the Bermuda Islands, and the Tasman Sea, respec- tively, trend toward less MgCOs in cooler water. This trend is superimposed on the high variability of the MgCOs; concentration found in Bairdia. The cold-water form (transect C, Tasman Sea) departs from the high-low-high pattern of MgCO; concentration prevalent in transects through valves from warmer water. It is suggested that this result may indicate that calcite in the outer part of valves of Bairdia and possibly other genera may be in equilibrium with sea water when it is secreted or, perhaps, later in the animal’s life. VARIATION DUE TO GENETIC DISSIMILARITY An indication of variation due to genetic difference has been observed. Based as it is on our very small sample size, it must be regarded as highly tentative. Interpretation is further complicated by the fact that neither Krithe nor Macrocypris is a typical member of its respective superfamily. Moreover, many of the specimens studied have come from the abyssal environment, the fauna of which is only now becoming well understood. Nevertheless, Text- figure 1 and Table 1 both show that cytheraceans may have a somewhat lower coefficient of variation than either the bairdiaceans or the cypridaceans. If this indication is real and is supported by further study, it will mean that individual cytheracean ostracodes show less variation in MgCOs; concentration through their carapaces than other ostracodes. In addition, the possible zona- tion of low- and high-magnesium calcite in Macrocypris suggests a basic dif- ference in the means of secreting carapace material between cypridaceans and some other ostracodes. Unfortunately, electron microprobe analysis appears to be ill-suited to the study of fossil or subfossil material, especially from cold water. Early diagenesis of the calcite may result in lowering the MgCOs concentration, just as the outer ELECTRON MICROPROBE OSTRACODE CARAPACE 583 part of the studied specimens of Bairdia and Macrocypris from cold water all had low concentrations of MgCO;. Alternatively, magnesium may be redistri- buted throughout the carapace. The principal evidence for this suggestion comes from study of the specimen illustrated in Plate 1, figure 5 (not included in Table 1). This specimen was without soft parts when it was collected, and it shows a much more uniform concentration of MgCOs; than specimens of Macrocypris containing soft parts. Its coefficient of variation was 17.22 com- pared to 42.86 for the specimen illustrated in Plate 1, figure 6 from the Tasman Sea. The mean value of MgCOs concentration was nearly the same for both specimens, suggesting redistribution of MgCO; throughout the carapace with diagenesis.’ ACKNOWLEDGMENTS The analyses were performed in the microprobe laboratory of the Division of Meteorites, Smithsonian Institution, Washington, D.C. We _ gratefully acknowledge the use of these facilities and the assistance of C. Obermeyer, J. Nelen, and E. Jarosewich. Research was supported in part by N.S.F. grants GB-4446, GA-12472, and GV-25157 to The University of Kansas and by a faculty travel grant from the University. All specimens studied will be de- posited with The University of Kansas Museum of Invertebrate Paleontology. REPERENCES CilED Cadot, H. M., Van Schmus, W. R., and Kaesler, R. L. 1972. Magnesium in calcite of marine Ostracoda. Geol. Soc. America, Bull., vol. 83, pp. 3519-3521. Chave, K. E. 1954. Aspects of the biogeochemistry of magnesium, 1. calcareous marine organisms. Jour. Geol., vol. 62, pp. 266-283. Dodd, J. R. 1967. Magnesium and strontium in calcareous skeletons: a review. Jour. Paleont., vol. 41, pp. 1313-1329. Foster, G. L. 1959. The constituents and their structural arrangement in ostracode carapaces. University of Kansas, unpublished M.S. Thesis, 88 pp. Foster, G. L., and Benson, R. H. 1958. The constituents and their structural arrangements in ostracode carapaces (abstr.). Geol. Soc. America, Bull., vol. 69, pp. 1565. Keil, K. 1967. The electron microprobe X-ray analyzer and its application in mineralogy. Fortschritte der Mineralogie, vol. 44, No. 1, pp. 4-66. Lipps, J. H., and Ribbe, P. H. Electron-probe microanalysis of planktonic foraminifera. Jour. Paleont., vol. 41, No. 2, pp. 492-496. Lowenstam, H. A. 1963. Biological problems relating to the composition and diagenesis of Sediments. In: Donnelly, J. W., edit.. The earth sciences. Problems and progress in current research, Rice University Semicentennial Pubs., Chicago, Chicago University Press, pp. 137-195. 584 H.M. Canot, R. L. Kagsier, AnD W. R. vAN ScHMUS Moberly, R. 1968. Composition of Mg-calcite of algae and pelecypods by electron microprobe analysis. Sedimentology, vol. 11, pp. 61-82. H. Meade Cadot, Roger L. Kaesler, and W. R. van Schmus, Department of Geology, University of Kansas, Lawrence, Kansas 66045 DISCUSSION Dr. H. Léffler: Can you use strontium in an analysis of this type? Dr. R. Kaesler: We could use strontium, but the difficulty with using it is that strontium is substituted in the aragonite lattice much more readily than in the calcite lattice. So it is not likely to be terribly abundant in an ostracode carapace. We would like also to look at some heavy metals such as zine, cadimium, and mercury. Dr. P. Sandberg: It would be interesting to make a comparison between your results and those of Dr. Oertli on relative states of carapace preservation. Dr. R. Kaesler: Yes, the very recent carbonate work is demonstrating that this diagenesis may occur early sometimes and it can happen without any apparent change in the way things look. EXPLANATION OF PLATE 1 Scale on all figures indicates 100 microns; arrows indicate direction of microprobe traverse. Figure 1. Bairdia sp. Specimen from Bermuda; oblique section; representing Bairdiacea. 2. Bairdia sp. Enlargement of Figure 1 showing two transects of microprobe analyses. 3. Krithe sp. Specimen from the Tasman Sea; lateral cross section; representing Cytheracea. 4. Cytherella sp. Specimen from the Tasman Sea; lateral cross section; representing Cytherellidae. 5. Macrocypris sp. Specimen from Tasman Plateau; without soft parts when collected; may have undergone slight diagenesis. 6. Macrocypris sp. Specimen from Tasman Sea; longitudinal cross section; representing Cypridacea. Plate 1 ELEcTRON MicropRoBE OsTRACODE CARAPACE 585 Cadot, Kaesler, and Van Schmus, Plate 1 THE CHITINOUS SKELETON AND ITS BEARING ON TAXONOMY AND BIOLOGY OF OSTRACODES Knup SCHULZ Zoologisches Institut und Zoologisches Museum, Hamburg ABSTRACT In the present paper the author discusses the systematical value of the ectoskeleton of ostracodes. This skeleton is composed of different chitinous rods and apodemes, which lie embedded in the surface of the body wall and serve mainly as a support for extremities, an attachment for certain muscles, and a screen, resp., support for other organs of the soft body. The morphological studies of the author show clearly: 1. The chitinous skeleton is of great importance for taxonomy and rela- tionship of ostracodes. 2. It is possible to homologize many different parts of the skeleton in higher systematical units, for example Cyprididae (-acea) and Cytheridae (-acea). According to that there is a chance of specifying the natural relation- ship of higher systematical units. 3. The finer morphology is of generic or even specific rank and value. 4. Some chitin features seem to be influenced by the biology of the species concerned, especially by their mode of locomotion and food intake. DE SOUELE RIE CHallOoNNEUxX Ei SON RAPPOR® SUR LA TAXONOMIE ET LA BIOLOGIE DES OSTRACODES RESUME Dans le travail actuel, l’auteur discute la valeur systématique de |’écto- squelette des ostracodes. Ce squelette se compose de plusieurs verges et apodémes chaitonneux, qui demeurent enfoncés dans la surface du mur corporel, et qui servent d’appui, principalement, pour les extrémités, un point de rattachement pour certains muscles, et un écran (resp.) d’appui pour d’autres organes du corps mous. L’étude morphologique de |’auteur montre clairement: 1. Le squelette chaitonneux est d’une grande importance pour la taxonomie et classification des ostracodes. 2. Il est possible d’homologiser bien des parties différentes du squelette dans des unités systématiques supérieures. Par exemple, Cyprididae (-acea), et Cytheridae (-acea). Selon cela il existe l’occasion de spécifier la relation naturelle des unités systématiques supérieures. 3. La morphologie fine est de rang et valeur générique, et méme spécifique. 4. Quelques traits du chaitin semblent étre influencés par la biologie de lespéce en question, surtout par leur mode de locomotion et d’ingestion alimentaire. INTRODUCTION Ostracodes differ from most other crustaceans by the lack of a solid armour of the soft parts. It must have been completely reduced during their long phylogeny. There is only a thin cuticle left on the body wall which can sometimes be strengthened by more or less strong muscle fibres below. The carapace represents a very effective protection against the harassment of the environment. It suspends the soft body within its valves by the aid of the adductor muscle. On the other hand there were evolving two different skeletal constructions during the ostracode phylogeny which could form attachment points for appendages and certain muscles or could serve as a support for the soft body itself. 588 K, SeHurz CHITINOUS SKELETON The first skeletal system is composed of different chitinous rods and lies embedded in the surface of the body wall. It supports the soft body especially in its ventral regions, gives abutment to several muscles and a stable base to the extremities. The other skeletal system, the endoskeleton, is completely encased within the body and often composed of a chitinous plate located in the centre of the body. This endoskeleton is of great importance for the suspension of the soft body from the carapace by a series of strong muscles. It is not proved in all ostracode taxa yet, but it is likely to be widespread. The external framework of the skin is divided into two sections, the so-called headcase and the thoracic framework. The latter represents the base for the trunk-limbs, furca, and copulatory organ. The thoracic framework does not exist in all ostracode groups. As an example one can take the frame- work of a cytherid, Semicytherura nigrescens Baird, 1838 (Text-fig. 1). The headcase is heavy chitinized and represents a two-piece capsule (Text-fig. 2). Its anterior helmet-shaped division encloses the forehead and upper lip and serves as an attachment for the first and second pair of antennae. The posterior part of the headcase begins at the mouth entrance and contains the hypostome or sternum which is the base for the mandibles, maxillae, and sometimes other extremities. The sternum and upper lip are fused together by the lower lip in such a way that both parts show only little freedom of movement in case of food intake. The headcase contacts the adductor muscle tendon by means of two strong apodemes in such a way that it is fixed in a certain place. The “antenno- labral apodeme” (Ala) arises from the lateral part of the upper lip, while the “anterior-hypostomal apodeme” (Aha) arises from the dorsal region of the sternum (Text-figs. 2-5). The chitinous skeleton of the trunk is well developed in only few ostracode taxa [such as Platycopa, Cytheridae (-acea) ], see Text-fig. 1). In most cases there cannot be noticed a special attachment for the thoracic limbs. The furca merely often has its own chitinous rod as a point of attachment for its muscles. There seems to exist a correlation between a crawling locomotion, the total lack of a dorsal muscular system of the soft body, and the occurrence of such a chitinous skeleton of the trunk in some ostracode taxa. My own morphological studies show clearly that position and shape of skeletal elements of cytherids, cypridids, and darwinulids are constant features within the species and very little exposed to any modification (Text-figs. 2, 3, 4). Moreover there is a good chance of homologizing certain skeletal ele- ments within the subfamilies of those groups, except in the sucking mouth of the paradoxostomatids, where upper lip, lower lip, and sternum are so per- fectly fused, that there is still no chance of homologizing. CHITINOUS SKELETON OSTRACODES 589 Semicytherura nigrescens Baird, 1838. Chitinous Skeleton of male soft body. Text-figure 1. j= K. ScHuLz 590 ‘o[sdeo-peay JO MOTA-IpI¢ “(OS8I ‘souo| ) DSO410} Slaplagay) —"Z aINBIf-}x9 J, 7VYO00Z O @) WNIT > 598 CHITINOUS SKELETON OSTRACODES ‘ajnsdvo-peay JO MarIA-apigS—(Z98T ‘Apelg) vuijps S14 £01949 FY — “¢ co IINSIF-}X9 T, 592 K. Scuuz a : Q é" \ ~. \ f Mi —Esophagus \ we a NEE as: PS I \ Ala wo. 3 } { Text-figure 4.— Darwinula sp. — Side-view of head-capsule. In general it is safe to say that with the chitinous skeleton there turns up a new area of features which can be of great value for taxonomy. With help of these structures there may be a better opportunity of clarifying the relationship of ostracode families such as cytherids, cypridids, darwinulids, and their subfamilies than has been possible by means of the carapace and appendages. A comparison with specimens of these three groups shows, that the forming of the chitinous skeleton is not induced by functional needs but could be traced back to a general basic form, which might be represented by the Platycopa. It looks by way of example as if the phylogenetic distance be- tween cytherids and cypridids is not very great. CHITINOUS SKELETON OSTRACODES 593 To demonstrate this we can take the rake-shaped organ of the Cyprididae (-acea) and the lower lip of Cytheridae (-acea) or Darwinulidae (-acea) as representing homologous organs (see fig. 6-11). Heterocypris, for example, has remarkably big teeth whereas in many other cypridid taxa they occur very small. These teeth correspond to a row of teeth respectively more or less strong bristles in the group of the cytherids (see fig. 8-11). Cyprideis has a number of small teeth which can just as well be of great value for the transportation of food particles into the atrium. Hirschmannia, Hemicythere, and Semicytherura show only a row of hairs. On the other hand there can be noticed a striking likeness in the lower lips in different ostracode families. In other words, these structures can easily be recognized as homologous organs. Moreover the lower lip, ¢.g., can serve as a good diagnostic structure for classifying some cytherid or cypridid taxa. (In this respect it is interesting to notice that Semicytherura (Cytheridae) shows more affinities to Paradoxostoma than to most other cytherids. The main skeletal elements of headcase or trunk are often of generic, sometimes even specific rank. On the other hand various species of one genus often differ only slightly in chitinous structures, ¢.g., there occur some secon- dary rods within the skeleton which can be decisive. A sexual] dimorphism can only have an effect on the construction of the thoracic skeleton, the headcase of both sexes are of total conformity. RELATIONSHIPS TO HABITS The ostracode mode of life shows more or less morphological effects on the general equipment of the chitinous skeleton. Thus, there is often to be observed a reinforcement of skeletal structures in bottom dwelling or burrow- ing cytherids. The shape of their headcase is more ball-like than the same structure of algae-living ostracodes. Hence it appears as a functional accom- modation to a stronger or weaker mechanical stress on the skeleton of these different ostracodes. Swimming ostracodes like cypridids require considerable space for their antennae. Therefore, in this group the first antenna is attached to the top of the forehead. It looks as if this is a secondary adaptation. The sucking mouth of the cytherid Paradoxostoma can be seen as a func- tional adaptability to the different mode of food intake. The upper lip and sternum are rigidly fused and the mandibles are enclosed within the headcase. The character of the teeth which are located at the mouth entrance of cytherids and cypridids (mentioned above) seems to be influenced by the nature of food. Hairs and bristles on the surface of the headcase show similar varia- tions, but the function of these elements is not absolutely clear. 594 K. Scuutz Text-figure 5.— Bairdia sp. — Side-view of head-capsule. CONCLUSION We see that with the chitinous skeleton there appears a new field of characteristic features, which can be, in addition to descriptions of carapace and soft body, of great value for taxonomy. It may be helpful in answering phylogenetic questions which are not yet solved. Knud Schulz, Zoologisches Institut und Zoologisches Museum, Hamburg, Germany CHITINOUS SKELETON OSTRACODES 595 Text-figure 6. — Darwinula sp. — Lower lip. DISCUSSION Dr. I. G. Sohn: How did you dissect the specimen to see the structures? Mr. K. Schulz: I heated the body in liquid potassium-hydroxide, stained it afterwards with “Direct Deep Black” and dissected the structures under. a stereo-microscope with fine minute needles. Dr. R. Maddocks: I’d like to know whether you work at all with the chewing apparatus? Mr. Schulz: Yes, but only with chitinous parts of upper lip, lower lip, and sternum. I have not worked on the attachments of muscles and their function in that region yet. 596 K. Scuuz Text-figure 7.— Heterocypris salina (Brady), 1862) — Lower lip. CHITINOUS SKELETON OSTRACODES Hy iy, - ; Fr 1 Of ir Rd ee: . ] ie we A .f \ SG UF | Fi oF :f ae pe. hea ' ; ! hi Esophagus seitl. Verankerung am hint. Teil des Olr, [ee mee fp Mf). iy J Ses ge.’ Se y ff / \ t \ : Manareae 52); n i B Ve - bh = AA! lee O Text-figure 8.— Cyprideis torosa (Jones, 1850) — Lower lip. 597 100% s K. ScuHutz ° ys, 4 as y 2) eer! a LEED SGAEZZ; 7 ae Text-figure 10.— Hemicythere villosa (G. O. Sars, 1865) — Lower lip. CHITINOUS SKELETON OSTRACODES 599 a ao Text-figure 11.— Semicytherura nigrescens (Baird, 1835) — Lower lip. - rs ra Sa” vain: red enieeyd a LE sug eae 4 : 7 ms 7 om BIOFACIES AND MICROSTRUCTURE OF HOLOCENE OSTRACODA FROM TIDAL BAYS OF DELAWARE FREDERICK M. SwAIN AND JOHN C. KRAFT University of Delaware, and University of Minnesota ABSTRACT Ostracoda of the tidal bays of southern Delaware occur in four presently recognized biofacies: (1) silty clay bay biofacies representing most of the area, Leptocythere spp.; (2) silty organic clay tidal-river biofacies with Cyprideis and Perissocytheridea; (3) tidal bay sand biofacies with “Haflo- cytheridea”’ and Campylocythere; (4) tidal marsh mud biofacies with Cytherura. The relatively weak calcification of the ostracodes and correspondingly heavy chitinization in the tidal bay collection makes possible a study of features of the carapace cuticle, i.e., epicuticle, and underlying procuticle. The epicuti- cle, here interpreted as being deposited as polyphenolic material by secretory setae, may reflect minute irregularities in the underlying calcified procuticle, such as pits and nodes. Surface hexagonal patterns of 0.2 micron diameter may represent heteroaromatic structure of epicuticle material. In Cytherura spp. epicuticle is laid down in plates that join along reticu- lating surface ridges. The outer surface of the procuticle is variously smooth, nodose, punctate, heterolabyrinthic or vermiculolabyrinthic. Further work is necessary to evaluate taxonomic usefulness of these variations but some characteristic pat- terns seem to occur. A variety of sieve plate patterns is represented in this collection. In Loxoconcha and Cytheromorpha, secretory setae are located so as to cover en- tire surface with epicuticle coating. The normal pore setae in Cytherura having crateriform rims are believed to represent secretory setae. The sieve plates in some cytheracean ostracodes may serve for emission of repellent or attractant substances or both. Parasitic diatoms scattered over surface of one species of the collection resembling a Monoceratina undergo progressive burial by epicuticle. They provide nodosity to this ostracode shell. Other examples of attached algae or bacterial filaments can be recognized in the collection. LES BIOFACIES ET LA MICROSTRUCTURE DES OSTRACODES HOLOCENES DANS LES BAIES RELEVANTES DE LA MER, DANS L’ETAT DE DELAWARE RESUME Les ostracodes des baies maritimes du sud de Delaware se trouvent dans quatre biofacies actuellement reconnues: 1. Les biofacies des baies de sol glaiseux et limonneux, représentant la plupart de la zone, Leptocythere spp.; 2. Les biofacies de sol glaiseux limonneux et organique, maritimes et fluviales, avec Cyprideis et Perissocytheridea; Les biofacies de baie maritime de surface sableuse, avec “Haplocytheridea”, et Campylocythere; 4. Les biofacies de boue et de marécage, relevantes de la mer, avec Cytherura. La calcification relativement faible des ostracodes et la chitinisation cor- respondemment forte dans la collection des baies maritimes rend _ possible l'étude des traits du cuticle du carapace, c’est-a-dire épicuticle, et la procuticle se trouvant par dessous. L’épicuticle, interprété ici comme étant déposité comme 602 F. M. Swarn anp J. C. KrarFr du matériel polyphénolique par des sétae secrétoires, pourrait réfléter des irrégularités minutieuse dans dans le procuticle calcifié qui se trouve par dessous, telles que des noyaux et de noeuds. Des formations héxagonales de 0,1 micron de diamétre représentent une structure hétéroaromatique de matériel de lépicuticle, possiblement. Dans Cytherura spp., lVépicuticle est situé en plaques qui se joignent au long de rides de surface réticulantes. La surface extérieure du procuticle est quelquefois sans rides et contient par fois des noeuds. Elle peut aussi étre punctate, hétérolabyrinthique, ou vermiculolabyrinthique. I] faudra encore du travail pour Jl’evaluation de lutilité taxonomique. de ces variations, mais quelques formations caractéristiques semblent se mettre en évidence. Une variété de formations de plaque en crible est représentée dans cette collection. Dans Loxoconcha et Cytheromorpha, les setae secrétoires sont situées de facon a couvrir la surface entiére d’un résidue d’épicuticle. Les setae nor- males des pores dans Cytherura, ayant des jantes cratériformes sont censés représenter des setae secrétoires. Les plaques en crible dans quelques ostra- codes Cytheriques peuvent servir dans ]’émission des substances de répulsion ou d’attraction, ou pour toutes les deux. Des diatomes parasitiques situés sur la surface de ]’une des espéces dans la collection, se ressemblant 4 une Monoceratina subissent une sépulture pro- gressive par l’épicuticle. Ils pourvoient 4 cet ostracode de Ja nodosité dans sa conche. D’autres exemples d’algues et de filaments bactériaux rattachés sont reconnaissables dans la collection. INTRODUCTION A small fauna of about 20 species of Ostracoda was collected from tidal bays in southern Delaware. The species are listed, together with their distri- bution and environmental characteristics, in Table 1. Specimens of each species have been studied by scanning electron micro- scopy and some of the features noted are discussed herein. In most instances the specimens of the assemblage are poorly calcified and in many the epicuticle is better developed than is typical of many marine ostracode assemblages, features which are unique enough to warrant a consideration of details of these carapace features. ACKNOWLEDGMENTS The work was supported by National Science Foundation Grant No. GP- 5604 to Kraft. William Osborn assisted with field work. Takako Nagase as- sisted with the preparation and scanning electron microscopy of the specimens. Dr. L. S. Kornicker and Dr. R. H. Bate kindly read the manuscript. OSTRACODE BIOFACIES Most of the ostracode-bearing samples studied were silty clay from Indian River Bay; a few other samples contained ostracodes in sand and marsh mud in that bay. In Rehoboth Bay and Little Assawoman Bay several samples of sand and silt contained ostracodes. Table 1 shows the data at each collecting station. Silty Clay Bay Biofacies. (Localities IR 177, 178, 181, 182, 208, 209, 212, 223, 227, 245, 247, 264, 268, RB 270, LA 282, 284). This material is characterized OsTRACODA TIDAL BAYS DELAWARE 603 by pH values of 7.1 to 7.6 and Eh values of —250 to +125 mv. Salinity is 28 to 30 o/oo. The sediment originated as mineral and organic detritus carried in by the tidal rivers. The ostracode species of this biofacies are: Leptocythere aff. L. castanea Sars, 1866 (Pl. 4, figs. 7 a, b; Pl. 5, figs. ia): L. aff. L. pellucida (Baird, 1850) (PI. 3, figs. 1 a, b) L. aff. L. crispata (Brady, 1868) (PI. 4, figs 6. a-c, 8 a, b) L. aff. L. angusta Blake, 1933 (PI. 4, figs. 5 a, b) L. cf. L. nikraveshae Morales, 1966 (PI. 4, figs. 2 a, b, 3 a, b, 4 a, b) Monoceratina? aff. M.? stimulea (Schwager, 1866) (Pl. 5, figs. 7 a-e) Echinocythereis? aff. E.? clarkana (Ulrich and Bassler, 1904) (PI. 5, Tae, Qe, 5) Eucythere sp. (Pl. 2, figs. 7 a, b) Cytherura vestibuiata Hall, 1965 (Pl. 1, figs. 4 a, b, 5 a-c, Pl. 2, figs. 1 a-d) C. aff. C. corensis Grossman, 1967 (PI. 2, figs. 2 a-c, 3 a, b) Cylindroleberis psitticina Darby, 1965 (Pl. 4, figs. 1 a, b) A species that occurs in this biofacies as well as in others of the area is Cytheromorpha aff. C. curta Edwards, 1944 (Pl. 3, figs. 2 a-d, 3 a-c, 4 a-f). Silty Organic Clay Tidal River Biofacies. (Localities IR 228, PC 197). The silty clays of Indian River and Pepper Creek contain: Cyprideis aff. C. locketti (Stephenson, 1938) (Pl. 2, figs. 5 a-c) Perissocytheridea brachyforma Swain, 1955 (PI. 1, figs. 1 a-f) The pH of the muds in this environment is 7.4 to 7.45 and the Eh is —105 to — 200 my. The salinity is 6 to 12 o/oo. These species seem to be primarily detritus feeders. Loxoconcha purisubrhomboidea Edwards, 1944 (Pl. 5, figs. 4 a-c, 5 a-c) and Cytheromorpha aff. C. curta Edwards, 1944, are also present in the tidal river muds. . Tidal Bay Sand Biofacies. (Localities IR 184, RB 273). The sand-bottom areas of Indian River Bay and Rehoboth Bay are characterized by stands of marine algae (U/va and others) on which the ostracodes occur. The pH values of the environment are 7.9 to 9.99 and the Eh values are +109 to +211 mv. The salinity is 30 o/oot+. The species of the sand biofacies are: Eucythere aff. E. triangulata Puri, 1954 (PI. 2, figs. 6 a-c) Proteoconcha? multipunctata parva (Edwards, 1944) (PI. 5, figs. 6 a-c) Paradoxostoma aff. P. hodgei Brady, 1870 (PI. 5, figs. 3 a, b) Haplocytheridea aff. H. setipunctata (Brady, 1867) (Pl. 1, figs. 2 a, b, 3 a, b) Tidal Marsh Mud Biofacies. (Locality Ir 212) One species, Cytherura cf. C. forulata Edwards, 1944 (Pl. 2, figs. 4 a, b) was found in the Spartina marsh muds bordering Indian River Bay. The area is characterized by pH value of 7.45 and Eh of —140 mv; the salinity was not measured. The ostra- code here is believed to be a detritus feeder. 604 F. M. Swan anp J. C. Krarr INDIAN RIVER BAY ASSAW BAY OMAN Text-figure 1.—Bottom-sediment types and ostracode collecting localities in southern Delaware. Sediments mapped by Kraft and students. 605 OsTRACODA TIDAL BAYS DELAWARE spleMpy viunI “/) “JZe Dygsowmosays4’) Aqieq vuiaypisg S149gaoa4purjts) (Apeig) vypjoundijas “FY ‘FFe papisayjhrojgv ULWISSOID $18U9109 “/) “JO DANAIYI4,) UIEMS DUsLOf{AYyIDILGQ VAPsIYIAIOSSI4I (Apeig) vandsis "7 "fy" 2490438901997 (Apeig) pod “5142 "'T “FFB I4ayjhr0jgaT ‘spiempy Vaproquoysqns -1ang “"T "J9 vyIU0I0xXOT ‘|eH VIVINGUSIa DAnAIYIA TD [[@H Vvjnqgiysaa vinsayih) [eH Pvyngysaa vansayjh/) SpIeEMpPY Vaproquoysqnsiang “TJ “f9 VY IUOIOXOT SpleMpy Vj4nI */) “Fye vy gsowo4sayja’) (uosuaydaig) 2772420] “s) “FFe srapiaday ayxe[g visnbuv "T ‘f¥e a4ayjhr0j1¢9T SI[BIOW, avysaavsyiu “TJ “Fo 2494149014 IT Apeig tabpoy ‘qd ‘Ffk puojsoxopvavg ‘ling VivjNbuvial “y “FJe asay pong splemMpy vivjns0f{ "7 ‘Jo vénsayyay) (preg) vpionpyjad "7 ‘f¥e 24aysh014 77 ‘ds asayjhong SSpleMpA Vj4ANI “s) “FF! py gsouosayiayy (spreMpqy) vaivg vyvjoundijnul § VYIUOIOIJOIg (tadeMyog) vaynwmijs ¢ Py “FFB EVUIY42I0U0 YT SI[BIOJA, avy Savy “T “fo 249414 I0}GIT SIBG DaUDISDI "TJ "FZe a4ayjhr01¢9T Sa]BIOW, avysaavsyiu “T ‘Jo 249414I0}G9T SIBG DaUDISDI “"T “Ze Ia4ayjhI01G IT (q pure Q) vuvysvja sig “ffv éstasaypdooury ry BpOde1sC, Avg uewomessy VI] ‘YT OO Stic 1ig+ 60T+ 661— CVn SO ‘pu OcT-+ SL = 00¢— 0S T— Grete 0+I— 0st— 0+o— QI = Sa 0ZI— Biesck SZt+ (Aw) 4a 6S°L OLL-CS'L 66°6-19°L £9°L-£0'L tL ‘piu CSL Hd Aejo Apues ‘AXIIg Keo Apues ‘AXIS pues Aj[IS sis Apues Ayo AXIS Aevjo Apues Aejo Ayis Apues Aevjo Aqis Apues Avp> AVIS Aeya AXIS Avpo Arg REE S pnw ysivpy Aero AQIS Avo Ais pues ABO AXIS Ava AVIS Aeyo AI1S Avo AXIS adAy, JUaWIIpIS al uolB00T $82 c8C £L2 OLZ L6l 89¢ $97 Lv2 S+Z (aang werpuy) 87272 Lee £27 cd 602 (4aATI 9t} yo you Iva) 802 $81 c8t I8T 8ZT LLY U0T}EIS ‘keg woqoyay ‘qy $4910 Jeddag ‘Od ‘Avg JaATY UeIpUy TI aIeMElaq jo Skvg [epi], Wolf EpooesIsO “T 9[qPL 606 F, M. Swarn anp J. C. Krarr SURFACE TEXTURAL FEATURES OF SHELL Ostracode shell structure.—The ostracode shell-structure nomenclature herein conforms to that discussed by Bate and East (1972, and this volume) and consists of the following. 1. Epicuticle, thin uncalcified outer organic covering of part or all of ostra- code carapace; little or no development of structure appears to occur in the epicuticle, but it may reflect structures in the underlying procuticle; organic matter is nonchitinous. 2. Procuticle-exocuticle, a relatively thin chitin-impregnated layer, calcified in most ostracodes, stained pink by Haemalum Eosin, underlying epicuticle; calcite crystals may terminate outward in several projecting patterns; 1.¢., reticulate-labyrinthic, nodose-labyrinthic, heterolabyrinthic, or exocuticle may be smooth-surfaced; represents outer part of procuticle of Richards (1951); not present in all ostracodes, particularly in some myodocopids. 3. Procuticle-endocuticle; forms inner part of procuticle; present in all ostra- codes and is calcified in most; composed of a lattice of elongate chitin fibres stained purple by Haemalum Eosin (Bate and East, 1972, and this volume) ; may contain pigment granules which give characteristic color patterns to certain ostracodes; overlies directly the epidermal cells of the ostracode animal. In the present discussion the material underlying the epicuticle will all be referred to as procuticle, because of the difficulty in distinguishing exo- and endocuticle in lateral-view photographs of the carapace. The ostracode animal may have at least two different kinds of setae emerging from pores in the procuticle. These may be large, thick, stiff and springlike in nature, or soft and appear to be fluid-filled in the living animal. After death the latter setae collapse (Pl. 3, fig. 3 c). The stiff setae have a protective function and in several instances are branched in the procuticle for further strength (Bairdia, Cypridopsis). The smaller setae are thought to be sensory and may also be secretory or other small setae may be only secretory. It is not clear whether two distinct types of these smaller setae may occur in the same individual (Omatsola, 1970, 1971). One function of certain types of setae is suggested by the writers to be secretion of the epicuticle. The chitinous procuticle of the ostracode is secreted by the epidermal cells, either entirely or mainly before molting, with calcifica- tion occurring after molting (Bate and East, 1972). The secretion of epicuticle involves a different biochemistry than that of the procuticle as it is composed of lipids and polyphenols rather than chitin. Features of the epicuticle.—Epicuticle is believed to be represented in most, if not all of the specimens studied here, but is not developed over entire exterior of carapace in several instances. It is not known whether certain areas that lack epicuticle in these specimens have lost it after death or whether it was never present. For example, in Haplocytheridea aff. H. setipunctata (Brady) (PI. 1, figs. 2b, 3b) epicuticle (dark areas) is lacking in the pit OsTRACODA TIDAL BAYS DELAWARE 607 Text-figure 2.— Part of surface of shell of Cytheromorpha att. C. curta Edwards from Locality 284, Little Assawoman Bay, Delaware, showing close- packed polygonal structure of cuticle surface around a sieve plate. Bar represents approximately 1 micron. areas (light areas) in specimens that still had appendages when collected. One of the functions, perhaps the main one, of the biochemically resistant epicuticle is probably to protect the bacteria-susceptible chitin of the procuticle from decay during life of the animal by continuing to lay down epicuticle where needed. Consistent absence of epicuticle in the pits of H. setipunctata may indicate an old individual no longer able to supply epicuticle requirements. The nodosity of the epicuticle seen in Perissocytheridea brachyforma Swain (PI. 1, figs. 1 b, c, f), Cytheromorpha aff. C. curta Edwards (Pl. 3, figs. 4 c, d) and minute pits in Leptocythere cf. L. nikraveshae Morales (PI. 4, fig. 2 b) are here considered to be structures reflected from the underlying procuticle surface. More sparsely nodose epicuticle surfaces as in Haplocytheri- dea aff. H. setipunctata (PI. 1, figs. 2 b, 3 b) and in Eucythere aff. E. triangu- lata Puri are less certainly reflected from the underlying procuticle; they may represent stockpiles of epicuticle substance that are used for repair of the epicuticle if needed. One feature of the epicuticle not reflected from the procuticle is the close- packed hexagonal pattern seen on part of the surface of Cytheromorpha (ar- rows Pl. 3, figs. 2 b, 3 c, 4c). This pattern having individual diameters of hexagonal structures about 0.2 microns (Text-fig. 2) is superimposed on the 608 F. M. Swain anp J. C. KrarFr minutely nodose pattern of diameter about 0.1 micron (1,000° A). The hexagons may represent either the aromatic structure of the epicuticle or microbial or mineral growths on epicuticle surface; the former explanation seems the more plausible. The epicuticle may have undergone partial condensation in those areas, thus reflecting the aromatic nature of the layer. In Cytherura vestibulata Hall (Pl. 1, figs. 4b, 5b; Pl. 2, fig. 1 b), some C. cf. C. corensis Grossman (Pl. 2, fig. 3b), and C. cf. C. forulata Edwards (Pl. 2, fig. 4b) epicuticle, and perhaps the underlying procuticle also, is ap- parently laid down in plates the margins and intersections of which lie along the narrow ridges of the valve surface. As two kinds of normal pores occur in C. cf. C. corensis (Pl. 2, fig 3b) it is not clear which one or both may con- tain setae that are involved in epicuticle formation. As discussed below, the pores that have raised rims around them may be the secretory pores. In one specimen of Cytherura cf. C. corensis (Pl. 2, figs. 2b, c) epicuticle appears to have been smeared-on irregularly perhaps to cover filamentous bacterial growths on surface. Epicuticle occurs in platelike fashion with marginal rims around some sieve plates in Loxoconcha cf. purisubrhomboitdea Edwards (PI. 5, figs. 5b, c). The burial of diatoms attached to the surface of Monoceratina? aff. M.? stimulea (Schwager, 1866) seems to be accomplished by laying down of epicuticle. Features of the procuticle.—The outer surface of the procuticle in the specimens studied here, in many instances as seen reflected in the overlying epicuticle is variably smooth, nodose, pitted, spongy, or irregular. It is un- certain whether the surface is formed of a matrix of chitin and calcite of which both, or only the calcite, are involved in the surface textural variations. In several instances in which epicuticle remains on part of the valve surface (PET, fig. 2b; Pl 2) fie, 7b: Pl 4, fies 4b: Pl. 5) fic. Sb) theresseemsntonve primary roughness and irregularity of the outer surface of the procuticle that is not entirely reflected in the epicuticle. Classification of the variations of procuticle surface texture of less than one micron is difficult, but the writers suggest the term labyrinthic for these non-smooth surfaces, with modifying terms of nodose (PI. 3, figs. 4 c-e), spongy (Pl. 4, fig. 2b, 4b), heterolabyrinthic (irregularly) (Pl. 2, fig. 7b), and vermiculolabyrinthic (winding and branching furrows). The latter type was not found in the present specimens but occurs in fresh-water Candona and Darwinula and in marine Pontocythere (Hulingsina). 1t should be emphasized that these features are 1 to 2 orders of magnitude smaller than the surface ornamental features generally described on Ostracoda. Features of seta pores and sieve plates. — Normal pores in which seta are associated with sieve plates in the present collection occur in Perissocytheridea brachyforma Swain, Haplocytheridea aff. H. setipunctata (Brady), Cythero- morpha aff. C. curta Edwards, Cyprideis aff. C. locketti (Stephenson), Eucy- there aff. E. triangulata Puri, Loxoconcha cf. L. purisubrhomboidea Edwards, OsTRACODA TIDAL BAYS DELAWARE 609 Echinocythereis? cf. E.? clarkana (Ulrich and Bassler), and perhaps in Proteo- concha ? P. multipunctata parva (Edwards). In the Perissocytheridea (Pl. 1, fig. 1b, f) the sieve plates lying on the ventral slope are smaller than those of the main valve surface. The sieve-plate setae occur both centered and uncentered in the plate and in the Cyprideis both types occur in the same specimen. In the Haplocytheridea the setae seem to be mostly centered; in the Loxoconcha mostly uncentered, in the Cytheromorpha centered, in Eucythere aff. E. triangulata centered and in the Echinocythereis ? uncentered. No physiological significance can at present be attached to these variations, but they may be useful taxonomically as observed by others (Puri and Dickau, 1969; Sandberg and Plusquellec, 1969; Omatsola, 1970). The setae in Loxoconcha cf. L. purisubrhomboidea and Cytheromorpha aff. C. curta (Pl. 5, fig. 5b; Pl. 3, fig. 4f) are arranged closely enough to each other to be able to cover the entire surface and presumably are secretory setae that function to produce the epicuticle. In the former species these setae rise from sieve plates while in the latter species they appear to be distinct from the larger sieve plate setae. Perhaps the sieve plate setae in Loxoconcha serve more than one function. Two kinds of normal pores occur in the Cytherura of this collection; neither of which is associated with a sieve plate. The larger pores (PI. 2, fig. 3b) lack crateriform rims whereas the smaller pores have calcified rims. The setae of the latter type of pore are here suggested to be secretory setae for epicuticle. The proximally knurled setae (PI. 1, fig. 1, d, e; Pl. 5, fig. 4c) are sug- gested to be of sensory function. Although the function of the sieve plates and of the large noncratered pores in Cytherura remains speculative they may serve as sites of emission of at- tractant of repellent substances or both. SYMBIOTIC OR PARASITIC ATTACHED ALGAE In Monoceratina? aff. M.? stimulea Schwager specimens of the diatom Cocconeis sp. are attached to the surface (Pl. 5, figs. 7c, d, e), in varying stages of preservation. It appears that the diatoms were in the process of being covered by epicuticle secretions when the specimens were collected. The diatoms in this case contribute to the ornamental pattern of the ostracode as node-formers. Other instances of diatoms attached to ostracode valves were noted (PI. 4, fig. 7b), but burying of these was not observed to take place except in Monoceratina? Several examples of filamentous algae? on fresh-water ostra- codes and a few marine ostracodes studies by the writers have been seen but in the present collection attached algae other than diatoms are relatively rare. In Cytherura cf. C. corensis Grossman (Pl. 2, figs. 2b, c) there are filamentous structures on the valve surface that may be algal. In the illustra- tions it appears that the filamentous structures were rather hurriedly covered by an irregular coating of epicuticle. 610 F. M. Swain anp J. C. Krarr CONCLUSIONS The Ostracoda discussed herein are typical of oligohaline tidal bays having pH values that fall in the general 7-8 range and negative Eh values, the latter indicating reducing conditions. The assemblage as a whole is dominated by Leptocythere spp. and Cytherura spp. Tentatively, four biofacies are recognized: (1) silty clay bay biofacies with species of Leptocythere, Cytherura and others, the principal biofacies of the area; (2) silty organic clay tidal river biofacies with a species of Cyprideis and of Perissocytheridea; (3) a tidal bay sand biofacies with species of Eucythere and of Paradoxostoma and Haplocytheridea; and (4) tidal marsh mud biofacies with a species of Cytherura. Epicuticle is well developed in most of the specimens and calcification is rather poorly developed as a reflection of the lime-poor environment. Incom- plete epicuticle in definite shell areas such as in pits of Haflocytheridea cf. H. setipunctata may be characteristic of old individuals in which secretory setae are not able to supply needs for new epicuticle. Assuming that epicuticle serves to protect procuticle and that secretory setae can replenish damaged epicuticle, small mounds of epicuticle in Haflo- cytheridea and Eucythere and craterlike only partly calcified deposits around normal pores in some species studied here are suggested as stockpiles for repair purposes. Very small close-packed hexagonal structures about 0.2 microns in diameter occur either as part of, or on, the surface of the epicuticle, the origin of this structure is uncertain but it may be the crystal structure of the epicuticle that has undergone partial condensation. In some Cytherura and covering the sieve plates in Loxoconcha, epicuticle, and perhaps underlying procuticle, seem to have been formed in plates with “distinct boundaries. The procuticle surface, presumably the calcified portion, essentially, is irregular in some ostracodes. The irregularities result in a labyrinthic pat- tern of the exposed procuticle after weathering of the epicuticle. The patterns exhibited by the surface ate variously characterized here as: punctate, or spongy, nodose, heterolabyrinthic, or vermiculolabyrinthic. The labyrinthic surface seems to be more typical of non-marine and brackish-water ostracodes than of marine forms. Setae, suggested to be secretory for the epicuticle, occur closely spaced in Cytheromorpha aff. C. curta Edwards, and Loxoconcha cf. purisubrhomboidea Edwards. In the former species the setae are not associated with sieve plates and do not have knurled sensory bases and perhaps are unifunctional, in the latter species the sieve plate setae may be polyfunctional. In Cytherura both large, unrimmed, and smaller, rimmed, normal pores bear setae. The smaller- pore setae are suggested to be rimmed with epicuticle material and calcite and to be the secretory setae. Diatoms in progressive stages of being covered over by epicuticle were noted in a species of Monoceratina? These are in part regularly spaced, as if OsTRACODA TIDAL BAYS DELAWARE 611 by design, on the valve surface. Other possible algal filaments covered by epicuticle were noted on a Cytherura sp. REFERENCES Bate, R. H., and East, B. A. 1972. The structure of the ostracod carapace. Lethaia, vol. 5, pp. 174- 194, Omatsola, M. E. 1970. Podocopid Ostracoda of the Lagos Lagoon, Nigeria. Micropaleon- tology, vol. 16, pp. 407-445, pls. 1-13. 1971. Campylocythereis, a new genus of the Campylocytherinae (Ostr., Crust.) and its muscle scar variation. In Colloquium on _ the Paleocology of Ostracodes. Oertli, H. J. (ed.), Bull. Cent. Rech. Pau-SNPA, vol. 5, suppl. pp. 101-123, 4 pls. Puri, H. S., and Dickau, B. E. 1969. Use of normal pores in taxonomy of Ostracoda. Gulf Coast Assoc. Geol. Soc. Trans., vol. 19, pp. 353-367, pls. 1-6. Richards, A. G. 1951. The integument of arthropods. Minneapolis, Univ. of Minn. Press, 411 pp. Sandberg, P. A., and Plusquellec, P. L. 1969. Structure and polymorphism of normal pores in cytheracean Ostra- coda (Crustacea). Jour. Paleont., vol. 43, pp. 514-521. Frederick M. Swain, John C. Kraft Department of Geology, Department of Geology University of Delaware, University of Delaware Newark, Newark, Delaware 19711 Delaware 19711, and Department of Geology and Geophysics University of Minnesota, Minneapolis 55455 DISCUSSION Dr. L. S. Kornicker: Were the specimens you dealt with living when collected? Is the decalcification caused by their residing in a reducing mud after their death, or did the living animals have little calcification? If the former, one might ask whether the ostracodes from sediments with positive Eh were as decalcified as those in sediments having negative Eh. Were the illustrated specimens living or empty when collected? Dr. Swain: Nearly all the specimens discussed and illustrated contained soft parts or remnants of the soft parts when collected. The poor calcification we believe is a primary feature and not due to decalcification after death. The point you raise as to the possible effect of Eh on the shells after burial is an interesting one, which we are not able to answer at the present time. In general, however, negative Eh conditions in accumulating sediments seem to favor preservation rather than destruction of calcareous shells. 612 Figure la-f. 2a, b: caw: 4a, b. 5a-c. F. M. Swain anp J. C. Krarr EXPLANATION OF PLATE 1 Perissocytheridea brachyforma Swain. a. Left side of shell; 56. b. Enlargement of midventral surface showing a sieve plate, sensory seta, and studded or finely nodose labyrinthic surface due to projection of portions of calcified procuticle into epicuticle; x 568. c. Enlargement of sieve plate with a median septum at base of which lies the sensory knurled seta; X 1,118. d, e. Enlargements of knurled seta; XX 2,795 and x 11,180 respectively. f. Enlargement of a ventrally located sieve plate of smaller size than preceding; x 2,795. Locality 197, Pepper Creek, Delaware. Haplocytheridea aff. H. setipunctata (Brady). a. Right side of shell; x 47. b. Enlargement of surface showing crowded pit areas that in part contain setae and poorly preserved sieve plates and sparsely nodose interpit areas that represent projec- tions of procuticle into epicuticle; around and in pits epicuticle absent and surface of procuticle is exposed; X 227. Locality 273, Rehoboth Bay, Delaware. Haplocytheridea aff. H. setipunctata (Brady). a. Left side of shell; x 47. b. Enlargement of surface of shell; x 227, showing depressions that in part contain poorly preserved sieve plates, and sparsely nodose interspaces; epicuticle interpreted as forming sur- face of interspaces; underlying procuticle exposed in pits. Locality 273, Rehoboth Bay, Delaware. Cytherura vestibulata Hall. a. Right side of male shell; X 103. b. Enlargement of part of anterodorsal surface showing normal pores and lines of intersection of plates of epicuticle and perhaps of the underlying procuticle in narrow surface ridges; x 1,030. Locality 245, Indian River Bay, Delaware. Cytherura vestibulata Hall. a. Right side of female shell; * 86. b. Enlargement of median sur- face; > 860, showing normal pores and intersection of plates of epicuticle and perhaps of the underlying procuticle in narrow surface ridges; surface covered with epicuticle; 4,300. Locality 264, Indian River Bay, Delaware. Piotee! OsTRACODA TIDAL Bays DELAWARE 613 F. M. Swain anp J. C. Krarr Plate 2 614 Figure la-d. 2a-C. 3a, b. 4a, b. 5a-c. 6a-c. 7a, b. OsTRACODA TIDAL BAYS DELAWARE 615 EXPLANATION OF PLATE 2 Cytherura vestibulata Hall. a. Exterior of right male valve; xX 81. b. Enlargement of part of median surface showing intersections of plates of epicuticle and underlying procuticle along narrow ridges and some normal canals; X 473. c. A normal pore and seta with a thickened rim; X 2,236. Locality 247, Indian River Bay, Delaware. Cytherura cf. C. corensis Grossman. ; a. Right side of shell; * 97. b. Enlargement of part of median surface; >< 559, showing epicuticle, with fibrous chitin of outer part of pro- cuticle reflected beneath it. c. Further enlargement of part of same surface; < 989. Locality 270, Rehoboth Bay, Delaware. Cytherura cf. corensis Grossman. a. Left side of shell; « 97. b. Enlargement of part of surface showing junction of plates of epicuticle and underlying procuticle along nar- row surface ridges, and normal pores of two types: (1) large with little or no development of raised rims and (2) small with raised crateriform rims; < 473. Locality 270, Rehoboth Bay, Delaware. Cytherura cf. C. forulata Edwards. a. Left side of an imperfect shell; x 99. b. Enlargement of part of surface showing normal canals and junction of plates of epicuticle and underlying procuticle along crests of narrow surface ridges; < 507. Locality 212, Indian River Bay, Delaware. Cyprideis aff. C. locketti (Stephenson). a. Right side of shell; x 25. b. Enlargement of part of surface show- ing sieve plate areas and normal pore seta of simple and branched type; X 249. c. Enlargement of a sieve plate area, normal pore and seta; surface covered with epicuticle; x 2,494. Locality 228, Indian River, Delaware. Eucythere aff. E. triangulata Puri. a. Exterior of right valve; xX 99. b. Enlargement of part of surface showing sieve plates, normal pores, and setae; X 507. c. Enlargement of a sieve plate area; surface covered here by epicuticle; 2,494. Locality 223, Indian River Bay, Delaware. Eucythere sp. a. Right side of probably immature setose shell; x 99. b. Enlarge- ment of surface showing epicuticle, the underlying exocuticle, and possibly a small portion of endocuticle near center of picture; & 512. Locality 208, Indian River Bay, Delaware, near mouth of Indian River. 616 Ostracopa TipAL Bays DELAWARE Plate 3 OsTRACODA TIDAL BAYS DELAWARE 617 EXPLANATION OF PLATE 3 Figure la,b. Leptocythere aff. L. pellucida (Baird). a. Left side of shell; X 85. b. Enlargement of seta, knurled proximally; x 8,084. Differs from L. pellucida in having sinuous longitudinal ridge. Specimen appears to have a heavily developed epicuticle. Locality 209, Indian River Bay, Delaware. 2a-d. Cytheromorpha aff. C. curta Edwards. a. Left side of shell; X 86. b. Enlargement of part of surface showing a sieve plate area, scattered secretory setae, and the close-packed polygonal structure of the cuticle surface around the sieve plate; x 2,150. c. Further enlargement of sieve plate, x 4,300 showing minute nodose cuticular structure of sieve plate surface and a few secretory setae. d. Further enlargement of a different sieve plate showing details of nodosity of cuticle surface; x 9,890. It appears that the nodose structures are reflected in epicuticle from underlying procuticle. Locality 284, Little Assawoman Bay, Delaware. 3a-c. Cytheromorpha aff. C. curta Edwards. a. Right side of shell; x 100. b. Enlargement of a sieve plate area; < 2,408, showing part of a seta on right side of sieve plate and minute nodose structure reflected in epicuticle from underlying pro- cuticle. c. Part of surface around a normal pore and seta (knurled proximally), and both nodose and polygonal structure of cuticle; > 2,408. Polygonal structures interpreted as being structure of epicu- ticle. Locality 228, Indian River, Delaware. 4a-f. Cytheromorpha aff. C. curta Edwards. a. Right side of weakly calcified somewhat shrunken shell; x 99. b. Enlargement of part of surface; x 512. c. Enlargement of part of area of preceding showing minute polygonal structure of epicuticle, minute nodose structure of procuticle and secretory setae; x 2,537. d. Enlargement of nodose and polygonal structures and setae; X 10,320. e. Enlargement of nodes showing small ridges on some of them; xX 51,170. f. Part of surface in a different area showing a normal pore and numerous secretory setae; xX 512. Locality 208, Indian River, Delaware. 618 Ostracopa TipAL Bays DELAWARE Plate 4 Figure la, b. 2a, b. 3a, b. 4a, b. 5a, b. 6a-c. 7a, b. 8a, b. OsTRACODA TIDAL BAYS DELAWARE 619 EXPLANATION OF PLATE 4 Cylindroleberis psitticina Darby. a. Left side of shell; « 47. b. Enlargement of part of surface; x 882, showing surface epicuticle. Locality 282, Little Assawoman Bay, Dela- ware. Leptocythere cf. L. nikraveshae Morales. a. Right side of a collapsed shell; x 112. b. Enlargement of part of surface; > 538, showing areas of smooth epicuticle underlain by spongy-textured procuticle. Locality 181, Indian River Bay, Delaware. Leptocythere cf. L. nikraveshae Morales. a. Left side of a partly collapsed shell; % 99. b. Enlargement of part of surface of shell showing spongy surface of procuticle and inter- vening pits lined with smooth epicuticle?; secretory setae occur in several places; & 516. Locality 227, Indian River Bay. Leptocythere cf. L. nikraveshae Morales. a. Right side of shell; « 56. b. Enlargement of part of surface; xX 560, showing areas of epicuticle, procuticle and secretory setae. Locality 178, Indian River Bay, Delaware. Leptocythere aff. L. angusta Blake. a. Dorsal view of shell; < 99. b. Enlargement of part of surface; < 516, showing roughened surface of procuticle and secretory setae. Locality 227, Indian River Bay, Delaware. Leptocythere aff. L. crispata (Brady). a. Right side of shell; % 43. b. Enlargement of part of surface of shell; X 434, showing areas of epicuticle on ridges and underlying procuticle. c. Part of first thoracic leg; X 869, showing setose fringe on outside lateral margin. Locality 264, Indian River Bay, Delaware. Leptocythere aff. L. castanea Sars. a. Left side of shell; « 108. b. Enlargement of part of surface show- ing irregular outer surface of procuticle; x 538. Locality 177, Indian River Bay, Delaware. Leptocythere aff. L. crispata (Brady). a. Left side of shell; & 97. b. Enlargement of part of surface showing epicuticle to be smooth on ridge crests, wrinkled oa slopes of depres- sions and terminating around normal pores; X 473. Locality 268, Indian River Bay, Delaware. F. M. Swan anp J. C. KRAFT Plate 5 Figure la, b. 2a, b. 3a, b. 4a-c. 5a-c. 6a-c. 7a-e. OsTRACODA TIDAL BAYS DELAWARE 621 EXPLANATION OF PLATE 5 Leptocythere cf. L. castanea Sars. a. Left valve exterior; X 56. b. Enlargement of part of surface, show- ing smooth areas of epicuticle, as well as roughened areas that re- flect structure of underlying procuticle; > 560. Locality 181, Indian River Bay, Delaware. Echinocythereis? aff. E. ? clarkana (Ulrich and Bassler). Immature shell. a. Right side of shell; * 110. b. Enlargement of nor- mal pore, sieve plate and part of proximally knurled seta; x 5,160, also showing minutely nodose epicuticle. Locality 177, Indian River Bay, Delaware. Paradoxostoma aff. P. hodgei Brady. a. Left side of shell; « 99. b. Enlargement of surface showing epicu- ticle, normal pore with narrow rim, and seta; 2,365. Locality 223, Indian River Bay, Delaware. Loxoconcha cf. L. purisubrhomboidea Edwards. a. Right side of male shell; « 45. b. Enlargement of part of surface; < 450, showing elongate sieve plate, normal pore and distal part of proximally knurled seta; 4,515; epicuticle surface is shown. Locality 264, Indian River Bay, Delaware. Loxoconcha cf. L. purisubrhomboidea Edwards. a. Left side of female shell; x 50. b. Enlargement of part of surface showing smooth but incomplete epicuticle, underlying granular procu- ticle, pits, sieve plates, norma] pores and setae; X 247. c. Detail of a sieve plate, normal pore and seta, and rimlike margin of epicu- ticle around sieve plate; a few chitin fibers in procuticle appear in lower part of photograph; xX 2,473. Locality 228, Indian River, Delaware. Proteoconcha ? P. multipunctata parva (Edwards). a. Left side of shell; x 45. b. Enlargement of part of surface, showing roughened surface of calcified procuticle, and a sieve plate; « 989. c. Detail of sieve plate; xX 4,515. Locality 184, Indian River Bay, Delaware. Monoceratina ? aff. M.? stimulea (Schwager). a. Right side of male ? shell; x 56. b. Right side of female ? shell; x 56. c. Enlargement of part of surface of 7a, showing surface of epicuticle and adhering specimens of Cocconeis in several stages of covering by epicuticle and of dissolution; x 516. d. Enlargement of part of surface of another specimen; xX 559, showing patterned nature of epicuticle that may have been caused in part by previous attach- ment of diatoms and two Cocconcis in different stages of entombment and dissolution. e. Enlargement of part of surface of 7b showing un- buried (upper right) and buried (upper left) Cocconeis; *« 593. Locality 182, Indian River Bay, Delaware. AN INTRODUCTION TO THE NUMERICAL PHYLOGENY AND CLASSIFICATION OF PARADOXOSTOMATID OSTRACODA, INCLUDING A REDESCRIPTION OF MACHAERINA TENUISSIMA (NORMAN, 1869) KENNETH G. McKEnzIE Riverina College N.S.W., Australia and Rocer L. KAESLER University of Kansas ABSTRACT Using 30 characters from 23 genera of paradoxostomatid Ostracoda, a phenetic study was conducted as a prelude to a proposed numerical cladistic study. The method to be used in the numerical study is discussed, and Machaerina tenuissima (Norman) is redescribed. UNE AVANT-PROPOS A LA PHYLOGENIE NUMERIQUE ET LA CLASSIFICATION DE PARADOXOSTOMATID OSTRACODA, Y COMPRIS UNE REDESCRIPTION DE MACHAERINA TENUISSIMA (NORMAN), 1869 RESUME En employant trente caractéres de vingt-trois genres de paradoxostomatid Ostracoda, on a procédé a une étude phenetique comme un prélude a |’étude proposée numérique cladistique. On discute la méthode a employer dans |’étude numérique et on décrit encore une fois le Machaerina tenuissima (Norman). INTRODUCTION Undeniably, fossils are not “sports of the devil” as they were labelled in Renaissance times (Adams, 1938) but are the actual remains of once- living organisms. They have been preserved in a sequence that can often be determined by careful study, and in many instances they have living descen- dants that evolved from them. The evolutionary history of organisms is their phylogeny, an understanding of which is dependent on knowledge of cladistics, the branching sequences in evolution; phenetics, the overall similarity of organisms irrespective of their taxonomic affinities; and chronistics, the sequence of events in the evolution of the taxon (Sokal and Camin, 1965). Thus, considering phenetics, one would not ordinarily regard two taxa as closely related phylogenetically if they are highly dissimilar. Moreover, con- sidering chronistics, one would not regard a Jurassic species as the ancestor of a Triassic one. The most difficult aspect of phylogeny to determine is the branching sequence, the cladistics. One obtains phenetic information directly from the study of organisms, living or fossil, and chronistic information from the study of the fossil record and the biostratigraphic framework of the enclosing rocks. But cladistic information is not preserved, and parent-daughter relationships must be inferred, usually from phenetic information and chronistic relation- ships. 624 K. G. McKenzie ano R. L. KAESLER Much of numerical taxonomy has been directed toward the study of phenetic similarity, and some biologists have been led to discount the signi- ficance of the fossil record in determining phylogenetic relationships. One of them has even referred in general to phylogenies that are based on the avail- able fossil record as a “phylogenetic fallacy” (Colless, 1967). Now it is true that one does not find cladistic information preserved in the fossil record, but the availability of chronistic information from the fossil record greatly improves the likelihood of reconstructing a phylogeny that is a close approxi- mation to the parametric one. Naturally, paleontologists maintain that clado- grams (family tree diagrams, often expressing the results of numerical analysis of branching sequences) should be reconstructed if necessary until they are consistent with evidence from the fossil record (Rowell, 1970). For Ostracoda, this fossil record is exceptionally long-ranging and diverse. The group, which ranges from Cambrian to Recent and from marine to fresh- water environments, comprises about 35,000 known species (H. V. Howe, per- sonal communication) with many more new fossil than living forms being described each year (Table 1). For this group, therefore, and for other groups with good fossil records, e¢.g., mollusks, bryozoans, pollen, Foraminifera, brachiopods, and trilobites, it is clear that fallacious evolutionary relationships are more likely to be established if the fossils are neglected than when they are incorporated into the study. THE PROBLEM Paradoxostomatid ostracodes range from Mesozoic to Recent. More than 20 genera containing some hundreds of species have been associated with the group. Their group systematic relationships have already been proposed (Orlov, 1960; Moore, 1961), and a suggested phylogeny of the genera has also been published (Text-figure 1, from McKenzie, 1969). It is McKenzie’s proposed phylogenetic tree that we shall test by the methods of numerical cladistics, modifying the result to be consistent with chronistic information. Few models such as McKenzie’s exist in the ostracode literature, and the use of the numerical test also breaks relatively new ground in ostracode research. In addition to testing the proposed phylogeny, we shall also make a phenetic study of the genera and compare it both with McKenzie’s proposed phylogeny and with the results of the numerical cladistic study. This paper includes a brief discussion of the methods of numerical cla- distics, the data matrix of characters from the paradoxostomatid genera, the results of the phenetic study, and a redescription of Machacrina tenuissima (Norman) (Norman, 1869). A complete presentation of the results of the numerical cladistic study and integration of the results with the phenetic and chronistic information will be presented in a later paper. METHODS Cladistic Methods The various numerical methods for deriving phylogenies have been re- viewed by Sneath and Sokal (1973). These methods yield either nondirected, nonrooted shortest connection networks or rooted, directed shortest connection NuMERICAL STUDY PARADOXOSTOMATIDS 625 Table 1. Numbers of new species of Ostracoda described (to the nearest 25), subspecies and nomina nova not included. Data from the Zoological Record, 1958-1968. Approximate Numbers New Species Described Year Fossil Living 1958 450 50 1959 300 125 1960 450 50 1961 150 50 1962 900 75 1963 400 125 1964 1000 150 1965 625 100 1966 475 175 1967 400 100 1968 650 25 networks, called Wagner trees. When deriving the former, it is usual to use only the known OTU’s, but in the Wagner method hypothetical intermediate taxonomic units (HTU’s) may be determined by the computer and _ inter- polated into the resultant cladogram. An assumption that is common to all techniques is that of minimal evolu- tion, 7.¢., the familiar principal of parsimony. Since the minimum number of evolutionary steps required to achieve a particular character synthesis is assumed to be closest to reality, these networks are strictly maximum flow net- works. The idea that evolution is parsimonious has been the subject of con- siderable discussion and some criticism, particularly by those who prefer to think of evolution as opportunistic. The two ideas are not incompatible, how- ever. Although a particular evolutionary pathway may not have been parsi- monious, nevertheless the only suitable a priori assumption for the sake of modeling is that a minimum number of evolutionary steps was involved in the real phylogeny. This is consistent with our general abhorrence of reversals of evolution, and hopefully any apparent reversals would be detected in time to allow for their coding as derived states. Other assumptions regarding the data matrices used in such methods include the following: 1) the characters used can be expressed in discrete states which differ among the OTU’s being studied; and 2) with most methods, the character states can be arranged in evolutionary order from primitive to derived before the cladogram is reconstructed. Further assumptions differ in the different methods. Thus, the Camin and Sokal (1965) method assumes that evolution is irreversible, but this assumption is not used in the Wagner method (¢.g., Kesling and Sigler, 1969). In any variation of a Wagner method the choice of an ancestor is an important first step, and equally important is the coding of ancestral character states. Here the different methods can vary. For instance, Kluge and Farris (1969) coded all the ancestral character states as 0, whereas Kesling and Sigler (1969) coded both ancestral and descendant character states in ac- cordance with criteria of primitiveness. It is essential to realize that for any well-defined group the ancestor may be a meld of specialized as well as of primitive characters. Therefore, the Kesling and Sigler rationale appears pre- ferable. 626 K. G. McKenzie anp R. L. KAESLER In this study the following considerations served to establish an evolu- tionary order when coding the character states: 1. It was assumed that ancestral taxa had more segments in their several limbs than do their descendant taxa, i7.e., that evolution had proceeded by a reduction in the number of segments. 2. It was assumed that absences of entire limbs, organs, or setal groups repre- sent adaptations rather than the primitive condition. In these cases the “normal” organization of the characters in question was considered to be primitive (coding 0). 3. Some character states were evidently special modifications to fit the habitat. For these characters the unmodified state was coded 0. 4. For some characters, their state in the genus belonging to the geologically oldest group was assumed to be primitive (the chorologic principle). 5. For some characters their state earlier in ontogeny was assumed to be primitive (the ontogenetic principle). Phenetic Methods The phenetic methods of cluster analysis and ordination have been dis- cussed repeatedly in previous literature, and we will not cover that well- worn ground again here. The reader is referred to the textbook by Sokal and Sneath (1963), the pages of Systematic Zoology since about 1960, and articles by Kaesler (1967, 1969, 1970) and Rowell (1967, 1969, 1970). Data Matrix For the analyses of paradoxostomatid phylogeny, a relatively small data matrix was compiled, at first for 23 genera and 30 characters. The characters were expressed in either two or three states. Characters from the carapace as well as appendage characters were employed, but no measurements were used. When this matrix was completed, it was apparent that the characters chosen did not allow the genera Luvula and Macrocytherina to be satisfactorily dif- ferentiated either from each other or from the genus Javanella. As we were unable to study the types of the first two of these genera in the time available, they were omitted from the analysis. Thus, the final matrix consisted of 21 genera (OTU’s) by 30 characters or 630 bits of information. For 53 bits we had no information, which represents about 8.4 percent of the matrix. The character and their states, coded according to the criteria established earlier, are entered below. Primary data on the genera used are given in Table 2. 1. Strength of Carapace 0) = strong; 1 =) moderately, strong; 32 fragile. 2. Anterior shape 0 = rounded; 1 = rounded in some species; subacuminate in others; 2 = subacuminate. 3. Surface ornament 0 = surface smooth; 1 = weak ornamentation such as striations, punctae; 2 = strong orna- mentation such as reticulations, pits, costae. 4. Sulcus = without a sulcus; 2 = with a sulcus. 5. Caudal process 0 = no cauda; 1 = cauda present in some species, absent in others; 2 = cauda in all species. 18. 19. 20. ZA. 22. 23. 24. Hye 26. 27. 28. 78) 30. NuMERICAL STUDY PARADOXOSTOMATIDS 627 . Inner lamella . Vestibules . Radial pore canals— type . Radial pore canals— length . Hingement . Frontal muscle scar . Adductors . Antennule—segments . Antennule—natatory setae . Antennule—terminal sensory bristle . Antenna—segments . Antenna—terminal claws Mandible—coxale Mandible—palp Maxilla Maxilla—epipod Fifth limb—protopod Fifth limb—protopod Eye Genital Hocker Mouth parts Color P III (seventh limb) Normal pore canals P III (seventh limb) 0 = regular inner margin; 1 = some species with an irregular margin; 2 = irregular mar- gin in most species. 0 = vestibulum continuous; 1 = broad an- terior and elongate posterior vestibules; 2 = broad anterior and posterior vestibules. 0 = simple, grouped; 1 = simple, spaced; 2 = branched, especially anteriorly. 0 = short anteriorly; 2 = relatively long anteriorly. 0 = adont; 1 = modified adont or lophodont; 2 = with terminal teeth, sometimes also with a crenulate median element. 0 = absent or weak; 2 = distinct. 0 = five; 1 = four in some species, apparently five in others; 2 = four. 0) sevens) 19 =" six; 2 fives 0h = present; 2) = absent 0 = normal; 2 = distinctly club-shaped. Oe stivel 2) tour 0 = three; 1 = two; 2 = one, usually with an accompanying bristle. 0 = coxale with several powerful teeth; 1 = coxale with indistinct teeth or finely serrated cutting edge; 2 = coxale styliform. 0 = three or four segments; 1 = two segments; 2 = non-segmented. 0 = normal (palp and three lobes); 1 = palp and one or two lobes; 2 = palp absent. 0 = two or three downward — pointing Strah- len; 1 = one downward — pointing Strahlen; 2 = no downward — pointing Strahlen. = two dorsodistal bristles; 1 = one dorso- distal bristle; 2 = one coarse dorsodistal claw. 0 = three proximoventral bristles; 1 = one proximoventral bristle; 2 = no proximoventral bristles. 0 = with eyes; 2 = blind. 0 = without Hocker; 2 = with Hocker. 0 = without modification; 1 = modified (by lower lip serration, attenuation, terminal jaws) but not suctorially; 2 = with suctorial modi- fication. 0 = without specific color patterns; 1 = with uniform color; 2 = often with highly specific color banding (in black, green, red, brown, purple). = without coarsely serrated distal spine on 2nd segment; 2 = with such a spine. 0 = simple; 2 = sieve-type. 0 = present; 2 = absent. 628 K. G. McKenzie ann R. L. KAESLER S eto le ce ee eS ee a Si os Sh a NS Ba gS a) ee ee ae ee Be TSS Sa— Sa |S Sos cr: tote © eS oe fal ee eset elec) nal [ARPS sSaalsalie| (SaeneeS SiSror> ae descent Se TS aL en ear ta Sm eae OP MO naa ee OE Ses! SB N eS [Lj eeoeeo | |] [eee a = as Hepa ss ron RN Ne =" fn Pert Pe Sp INS Bada ot be | z oe [diene o> rSr>-4]) fell yey Se St SS 2a ™ & ‘© Le eS NUS e er |) eS SOEs 5 a Vay Ne ee oe | eee n 5 nl D Sof Pet OSL OWT feelin STIS Ie gSs! CU eR Stig = - sal - a G NINANANHATNNANANNOCA A HWA be | L FAINANAAANANAANANNCACACCA bl o 3 SINNN HT NNANAANNANCNCH HHO a ™ as AINNNDSDSCOCSCNNANNCSCSCOHOCS SG e CINAN NAN wr wre wQNnNnandCcownHrnaArre ew ao} = NlaenR RANA KR Ke KTR COC HH HR HHO o ah Silos So So oO AO Clo Cc Oo oe oo et oo re) aad MIONSCTOCSCONNNNCC OR FAO n S SoCo SOO oor o ogo oro OS Ono ~ oe aa eo Oo Colo So So S oc Se oo So Oo. u = NIST ONDONNDCC OCH ONOCOCNAAA = ms | ooc;§}j”cvhcUcmrmrrmC eC COUCUCOCUrRCUrHR CUT COCR RR Oe On er nT oS = rs) zo) =| Ss] 78) AS me) 3 od a a & a a c 5 & ay as ig 2@éeé& = ba Se =e z S wv oO mio oe 1) 3) Hoa 2S = aos HG aH @ fol vo <1 — — CO om V os = ass Ss aoe aS oS a i= Gl Gel = Sas, & Poets S tS xs hal RSet ap Er SS nc) SS 4 Se SS ey Sp ee o HSlliceo: Ovo! OOo Sl Se mOMOn Om On ie Ouomd wa) Vieot ee HH SSCs SH eo oO aA Se — Sloe Hee 2 2 > 8S 2 Ss 2 HH Bf 3 Vie SCHRMOMES OSE a DO Ree Gas Ol4MAARMOAUVQArADOAA AAS 0 0 2 0 Oo 47 Oo o 4% oo 0 Y) & O O © 4) @ O 4 | 1 OO OO Oo Om a Oo OH @ O @ 4 oO 0 @ O W @ 1 1 1 1 1 1D OFNO) Ziel, 92) 62 0S 200 OR Oke: 2 OR Zee Omen) 00 02 2 2 320 Om 25), BO OneO) 2 205 (0; 42 02) 20 2 ib 7 1) 0) 1 1 1 1 ) 0 2 0 00 2 1 1 1 i 1 1 1 O00 OROma OOOO a) 0) 0 0 1 1 i 1 0 0 2 2 2 2 2 Laocoonella Aspidoconcha Parvocythere Pseudocythere Redekea NuMERICAL STUDY PARADOXOSTOMATIDS 629 EXPECTATIONS As maximum flow networks, the cladograms at each branching or node associate groups (either OTU’s or HTU’s) with the greatest overall simi- larity, not in a phenetic sense but in the directional sense in which the data are coded from primitive to derived states. Under most circumstances, forms which show considerable overall resemblance to each other also satisfy the cladistic criterion of recency of common ancestry advocated by Bigelow and adopted by Hennig (1966), although there are several exceptions to this that are dealt with below. (Note that here recency carries no chronistic connotation but rather refers to the relative sequence of branching events.) The excep- tions fall into two broad categories: 1) anhomeomorphic situations, in which overall resemblance separates OTU’s which in biological reality are mono- phyletic, and 2) homeomorphic situations, in which overall resemblance asso- ciates forms which in biological reality are not monophyletic. Anhomeomorphic Situations Anhomeomorphy means morphologic dissimilarity and is a general term em- bracing the continuum of those dissimilarities which separate forms which in biological reality are monophyletic. Anhomeomorphy thus understood in- cludes divergences, such as those expressed by closely-related forms which have adapted to different environments, and polymorphism. For example, in bisexual groups of animals, sexual dimorphic characters distinguish males from females. It can happen that in matrices which incorporate both male and female characters somes OTU’s are included which have been described only from males or females. This is particularly the case where the matrices are partly based on data extracted from descriptions in the older literature. The expecta- tion in this case is that males and females may line up along different branches of the resultant cladogram. Homeomorphic Situations Homeomorphy means morphological resemblance and is a general term embracing the continuum of those resemblances which associate forms which in biological reality are not monophyletic. Homeomorphy thus understood in- cludes parallel development, convergence, and the various types of mimicry, the common adaptations which follow from a common habit of life. In clado- grams, homeomorphs may be expected to cluster on adjacent branches when- ever data matrices are based largely upon their homeomorphic characters. PRELIMINARY RESULTS As was mentioned earlier, it has not been possible for us to complete the analysis of the results of the numerical cladistic study. Text-figure 2 shows the results of the phenetic study in which euclidean distances between genera were clustered by the unweighted pair-group method. The phenogram is in no sense a phylogenetic tree; instead it represents the phenetic distance be- tween genera on the basis of the 30 characters on which the study was founded. 630 K. G. McKenzie anv R. L. KAESLER As would be expected, the phenogram displays many fundamental] dif- ferences from the suggested phylogeny (Text-fig. 1) proposed by McKenzie (1969). Note, for example, the closeness of Microcythere and Cobanocythere in Text-figure 1 and their marked dissimilarity in Text-figure 2. Similarly, in the phenogram Javanella is not differentiated from Luvula and Macro- cytherina, probably because of the lack of characters from the carapace, al- though Javanella is distinct in Text-figure 1. Assuming that the cladogram in Text-figure 1 represents the true phylogeny, the phenetic difference between Microcythere and Cobanocythere must be regarded as due to anhomeomorphy. Discrepancies between Javanella and Luvula-Macrocytherina are due simply to differences in weighting of information about the three genera. Neverthe- less, many genera regarded by McKenzie (1969) as closely related phylo- genetically are also closely similar phenetically. AGE L.Meso. Barrem. T Lee Ty Q Bythocytheridae Paradoxostomatids incertae sedis Paracytherois (1) Machaerina Paradoxostoma (2) Cytherois (3) ; Redekea Laocoonella Paracythere Sclerochilus Pellucistoma Javanella (4) Luvula/Macrocytherina Cobanocythere Microcythere (5) Cytheroma Pontocytheroma Paracytheroma Megacythere (6) Text-figure 1.— Proposed phylogeny of some paradoxostomatid Ostracoda (from McKenzie, 1969). NuMERICAL STUDY PARADOXOSTOMATIDS 631 | 0.0 2.0 [eee ee ee ee DISTANCE 1.0 Text-figure 2.—Phenogram prepared by the method from a matrix of distance coefficients. Cophenetic correlation coef- ficient equals 0.836. Megacythere Boldella Luvula Macrocytherina Javanella -Pellucistoma Paracytheroma Cytheroma Pontocytheroma Cobanocythere Cytherois Paradoxostoma Paracythe rois Acetabulastoma Machaerina Paracythere Aspidoconcha Redekea Laocoonella Parvocythere Sclerochilus Pseudocythere Microcythere unweighted pair-group 632 K. G. McKenzie anp R. L. KAESLER SYSTEMATIC SECTION Machaerina tenuissima (Norman, 1869) Text-figs. 3-16 Bythocythere tenuissima Norman, 1869. Xiphichilus tenuissimus (Norman), Brady, 1870. Machaerina tenuissima (Norman), Brady and Norman, 1889. Refer to Howe (1962, pp. 138, 246) Type locality. — St. Magnus Bay, Shetland. Location of types. — British Museum (Natural History), Norman Collec- tion. Redescription. — Carapace large (female about 1 mm); surface smooth; anterior narrowly subacuminate, posterior narrowly subtruncate; dorsum con- vex, slightly inflexed posterodorsally; venter also convex, slightly inflexed anteroventrally; general shape in lateral view subelliptical. In dorsal view subelliptical, compressed; ends acuminate; greatest breadth approximately medial. Internally, inner margin regular; line of concrescence inflexed antero- ventrally almost reaching the inner margin; thus the vestibule is continuous (Text-fig. 3); radial pore canals number about 10 anteriorly, 6 ventrally, and 5 posteriorly, totaling 20 to 25; they are short anteriorly, longer else- where, and some are thickened medially; normal pore canals scattered, rela- tively few, simple; adductor muscle scar pattern consists of an oblique row of four large scars; frontal and mandibular scars apparently very indistinct since they were not observed in the specimen illustrated; hingement weakly lophodont, with terminal projections in the right valve and a corresponding accomodation in the left valve. Antennule slender; 6-segmented; length ratio of the segments 16:20:19:- 18:6:5; setation weak comprising a setule each on the 4th and 5th segments and two terminal setules (Text-fig. 4). Antennal endopod 4-segmented; length ratios 10:13:16:4; setation includes a relatively powerful terminal claw; exopod 3-jointed (Text-fig. 5); antennal gland lobate (Text-fig. 6). Oral cone sub- triangular, modified suctorially (Text-fig. 7). Mandible coxa styliform; palp slender, 4-segmented, the terminal segment very small, setation all on the penultimate and terminal segments (Text-fig. 8). Maxillule elongate, slender; palp with two terminal setae; two slender lobes each with fine terminal setules and a third lobe reduced to a seta (Text-figs. 9, 10). Thoracic limbs pediform, 4-segmented; increasing in size from P [ to P III; P I and P II with powerful dorsodistal claw-like setae on the protopods; P III with a single slender dorsodistal protopod seta; P II and P III each with a single powerful distal spine on the 2nd segment; 4th segment of the P II hirsute; 4th segment of the P III serrate; terminal claws of the P II and P III (at least) distinctly spinulose (Text-figs. 11-15). Posterior portion of the body produced into a single hirsute spine-like process (Text-fig. 16). The above description is that of an adult female. A male could not be found in the material examined. All specimens examined were confined to species against the syntypic collection. NuMERICAL STUDY PARADOXOSTOMATIDS 633 Text-figures 3-16.— Carapace of female. 4. Antennule. 5. Antennal end- opod. 6. Antennal gland. 7. Oral cone. 8. Mandible palp. 9, 10. Maxillule palp. 11-15. Thoracic limbs. 16. Posterior portion of body. 634 K. G. McKenzie anp R. L. KarEsLer Dimensions. — Adult female: length 1 mm; height 0.3 mm; breadth 0.2 mm; all approximate. Localities. — Fairlie, Firth of Clyde; 5 fathoms; collected by A. M. Norman, F. R. S., in July, 1885. In the Norman Collection, B. M. (N. H.) 1911.11.8., M2769. Cumbrae; collected by G. S. Brady, F. R. S., and D. Robert- son, 13 August 1888. In the Norman Collection, B. M. (N. H.) 1911.11.8., 36506-36510. Discussion. — Machaerina, from this redescription, is evidently closer to Paradoxostoma than it is to Paracytherois, especially in the oral region. Further, the mandible palp in Paracytherois is usually described as non- or weakly segmented. In Machacrina, the segmentation is distinct. In shel] char- acters the genus is distinguished by its two pointed ends and by the knife- edged venter, the latter feature accounting for the generic names by which it has been known. The arrangement of adductor muscle scars is closer to that in Paracytherois than it is to the Paradoxostoma pattern. The genus probably ranges worldwide although it has been collected only infrequently. Its known range extends from Shetland through the Mediter- ranean to Australia. REFERENCES CITED Adams, F. D. 1938. The birth and development of the geological sciences. Williams and Wilkins Co., Baltimore, 506 pp. Brady, G. S. 1870. Notes on Entomostraca taken chiefly in the Northumberland and Durham district (1869). Nat. Hist. Soc. Northumberland and Durham, Newcastle-upon-Tyne, Trans., vol. 3, pp. 361-373. Brady, G. S., and Norman, A. M. 1889. A monograph of the marine and fresh-water Ostracoda of the North Atlantic and of northwestern Europe. Section I. Podocopa. Royal Dublin Soc., Sci. Trans., ser. 2, vol. 4, pp. 63-270. Colless, D. H. 1967. The phylogenetic fallacy. Systematic Zoology, vol. 16, pp. 289-295. Henning, Willi 1966. Phylogenetic systematics. Univ. Illinois Press, Urbana, 263 pp. Howe, H. V. 1962. Ostracod taxonomy. Louisiana State University Press, Baton Rouge, 366 pp. Kaesler, R. L. 1967. Numerical taxonomy in invertebrate paleontology. In Essays in paleontology and stratigraphy (Curt Teichert and E. L. Yochelson, eds.), Department Geology, Univ. Kansas, Spec. Pub. 2, pp. 63-81. 1969. Numerical taxonomy of selected Recent British Ostracoda. In Taxonomy, Morphology, and Ecology of Recent Ostracoda (J. W. Neale, ed.), Oliver and Boyd, London, pp. 21-47. 1970. Numerical taxonomy in paleontology: classification, ordination, and reconstruction of phylogenies. In Computers in Paleontology (E. L. Yochelson, ed.), North American Paleontological Conven- tion, 1969, Symposium 5, pp. 84-100. Kesling, R. V., and Sigler, J. P 1969. Cunctocrinus, a new middle Devonian calceocrinid crinoid from the Silica Shale of Ohio. Museum Paleontology, Univ. Michigan, Contr., vol. 22, pp. 339-360. NuMERICAL STUDY PARADOXOSTOMATIDS 635 Kluge, A. G., and Farris, J. S. 1969. Quantitative phyletics and the evolution of anurans. Systematic Zoology, vol. 18, pp. 1-32. McKenzie, K. G. 1969. Notes on the paradoxostomatids. In Taxonomy, morphology, and ecology of Recent Ostracoda (J. W. Neale, ed.), Oliver and Boyd, London, pp. 48-56. Moore, R. C., editor 1961. Treatise on invertebrate paleontology. Part Q. Arthropoda 3, Crustacea, Ostracoda. Geol. Soc. America and Uniy. of Kansas Press, 442 pp. Norman, A. M. 1869. Shetland final dredging report. Part II. On the Crustacea, Tuni- cata, Polyzoa, Echinodermata, Actinozoa, Hydrozoa, and Porifera. British Assoc. Ady. Sci., pp. 247-336; suppl. pp. 341-342. Orlov, Y. A. 1960. Basic paleontology: Arthropoda-Trilobitomorpha and Crustacea- morpha. Moscow (in Russian), 516 pp. Rowell, A. J. 1967. A numerical taxonomic study of the chonetacean brachiopods. In Essays in paleontology and stratigraphy (Curt Teichert and E. L. Yochelson, eds.), Department of Geology, Univ. of Kansas, Spec. Pub. 2, pp. 113-140. 1969. Numerical methods and phylogeny of the Calceocrinidae. Jour. Int. Assoc. Mathematical Geology, vol. 1, pp. 229-234. 1970. The contribution of numerical taxonomy to the genus concept. In The Genus; A basic concept in paleontology (E. L. Yochelson, ed.), North American Paleontological Convention, 1969, Sym- posium 6, pp. 264-293. Sneath, P. H. A., and Sokal, R. R. 1973. Numerical Taxonomy. W. H. Freeman and Company, San Fran- cisco, 573 pp. Sokal, R. R., and Camin, J. H. 1965. The two taxonomies: areas of agreement and conflict. Systematic Zoology, vol. 14, pp. 176-195. Sokal, R. R., and Sneath, P. H. A. 1963. Principles of numerical taxonomy. W. H. Freeman and Co., San Francisco, 395 pp. Kenneth G. McKenzie, Roger L. Kaesler, School of Applied Science Department of Geology, Riverina College University of Kansas, Box 588 Lawrence, Wagga Wagga N.S.W. Kansas, 66045 Australia 2650 DISCUSSION Dr. J. Hazel: Did you try that last dendrogram with anything other than euclidian distances ? Dr. R. Kaesler: We also clustered correlation coefficients, and I think Ken may have used Manhattan distance. Dr. Hazel: Did you like the correlation dendrogram? Dr. R. Kaesler: It didn’t bother me too much, but in general I don’t like using correlation coefficients in this way. 636 K. G. McKenzie AND R. L. KAESLER Dr. Hazel: It has been my experience that with bioassociational data the clustering of correlation coefficient (r) matrices or Cos © matrices results in more meaningful dendrograms than does the clustering of distance matrices. Dr. Kaesler: I brought the correlation dendrogram with me if you would like to look at it. Dr. Hazel: I have spoken with other workers who have got the results and also can’t seem to explain it. Dr. P. A. Sandberg: I was wondering what influence on clustering is produced by forms for which you have carapace only? Dr. Kaesler: In the case of the phenetic clustering it is quite dramatic when you compare Machaerina with Pellucistoma. INDEX AUTHORS A Sey Ni 402, 416 : Ergorens BWe ee SPA Abushik, A. F. ............ 88, 89, wp, 92, EeeaeRte. Ie von, 19 45 Adamczak, | eee 90, 96 Bertels, WARE SF Fe sae See Be 25, Adams, F. D. ............ 134, 623, 634 Be Akatova, N:.A. ............ 382, 383, 392, euee Were aie Ringe eG: 330,337 Blackith, R. E. .......... 142, 144, 473, Alm, G. were ee wees es eeeeseeses 150, 163, 170 Blackwelder, B. W. se 469, 485 Ameghino, F. ............ 328, 332, 337 Blakeni C2. 5. Sees 129, 136 Anderson, F. W. ........ 63, 64, 71, 72, Blanton. y 467 4 110, 111, 123 om ae i sei duaheecnae Yaa Le Andersen, H. V. ........ Dig clin eo SRS ai ee 122) 286. Andreiff, 1 ty aaeeeataeneaael 290, 292, 296 baa PNET. 1G eee S2inoon Amid Re... 290, 292, 296 Bold, W. A. van den .. 355, ee vee Apostolescu, V. .......... 267, 324, 337 Boltovskoy, E. ........... 324, 329, 333, Arx, W. S. von. ............ 467, 483 396.936, 520 Ashworth, A. ©. ......:: 306 Bonadureae 330 "340 258 Atkinson, L. P. ............ 466, 467, 468, Sin reece 366,411. 412 486 i Bouligandy ve 530, 532, 534, 536, 537 B Bowmantwi Ey =... 130 BradyecGiSt |. .cucs 132, 136, v7, Bapim@t Ti Be ssccescvsse: 267 196, 201, 246, BUY O. Lae ecesvessces 324, 338 247, a pete Baranovskaya, O. F. .. 402, 416 339, 354, 355, nico 226, 243 366, ia Barrett, E. M. .............. 132, 136, 138 oe e5, Barthelmes, Detlev .. 219, 221 pee aan Bartlett, M. §. ............ 61, 69, 71 fea aon Bassler Rams: ccecc-.---- 87, 88, 89, 90, y Lip 97.93 332. Brooks, Hs] CSA ane eee 294, 296 a 340 BrOOkSe Werke aces ele Brophy, Js Ave secs sc. TSeE RIAD ENG ccs cos ccaccaee 355, 366, 529, pe aay ene 535, 537, 538, ye 539. Bon 552, IBIRON ATE, \Wha. shgeseoscuatesdedecx 1390, 269 554 606 611 Bruce; Jel. tance: 218, 221 Eaulies) OOF)... "319,349 Bumpus, D. F. ............ 466, 467, 484, Becker er De. .ccniee 328, = yi nas ee 434, 442 Beckner, M. ............... 19, 44 Buzas, IME PAE ce 475, 481, 484, Benda, W. K. ........... 476, 483, 490, ooo 498 ipysragoral, Tk, JEL. sosscsoeseee 14, 16, 18, 19, re 44, 79, 85, 86, 247, 262,286, Cadot, H. M. ............... 226, 243, 578, 291, 296, 330, 579, 580, 583 397-839; 958%) CalinW@Al Re occ. 134, 136 354, 356,366, Camacho, H. H. .......... 327, 328, 332, 434. 442. 476, 339 483.538,551, Camino J. H. ............:. 623, 625, 635 552-bo4eaitie (Caralip Mace sect -cc a 411, 413 583) (Carbonelaba eee 447, 460, 461 637 INDEX AUTHORS Carbonnel, G.....:..)....% Diie2762200, “Delorme, Ll. D:*_4...... 306, 434, 442 286, 290/292, Dennell Reg -.--..0.- 530, 537 B94N096'" “Deroas "G. “in ..n. cee 268 CATE, SOA MEE Ms as:.58a ee 404° Table’, Desehiens, Re o.:..0:<..<-- 218, 221 between p. Dickau, B.-E. .............. 609, 611 406-407, 413 Dingle, R. V. .............. 324, 339 Catzigras: Vs sci s 290), 2925296 -Dodd.d. jRaie.6- ee 577, 583 GCavielier, (Che scrcccseceee 271, 280,290, d’Orbigny, Alcide ...... 332, 339 292996 Drach MAP... 530, 537 Cerame - Vivas, M. J. .. 465, 466,469 | Dumon, J.C. ................ 411, 413 484 Chapman, G. .....:«....-. 173, 174, 175, & ZU TEASE OB Ay occ ee 529, 533, 534, Chateauneuf, J. J. .... 290, 292, 296 535, 537, 538, haven Ke Ree 577, 582, 583 539, 551, 552, Chestnut, Accel, Aero 130 554, 606, 611 Christensen, O. B. ...... 66,71 Edmundson, C. H. ...... 134, 136 LO) bs) at Seen 992,554 Edwards. N. ............< 275, 280 Clayton, Ta. :...:...s0654. 306° Hlofson,O. 2.2... 15, 16, 45, COIS MEAT. basco serccees 132, 134, 136 155, 164, 191, Coleman,(G! L,, I1....... 476, 483 192, 197, 201, Collesswa MOEN, ms.c.005-- 624, 634 382, 383, 387, Colman ds ees soe 173, 174, 175, 393, 394, 414 179, 1S Ots Misey. CR... ee 134, 136 194 aS Ook.” Witon, CS: 52 132, 134, 136 199, 201,203 Wnegel, P. To. 476, 484 Colombe is 290,292,296 “ByanseR. GG... 195, 201 CooperniG Mls ace 111) 122 Hyenson: 4 D. 6.8. 121,493 Copeland: avi Je 2... 89, 90, 91, Pie OF. At. 122 F riado, Roque P. ........ 319, 339 : 2 Crosskey, H.W... $95,Table 5, reiiden, H.W. 392, 394,414 etween p. 406-407, 409. BSE ale? AS Ai ccanccurcseces 458, 460, pie 413 _ Gpoddh, We eee nnn. asorGaNIGSl Taga ee ne Curry, Dee oe 271, 280 Filatova, ar os ee 383, 401, 410, Cushman, J. _ Niece 129: 136! “pose oon Yoa ~ O 414 ELLER Sig AUN ces 306” WiEhieNBONe 2. 530, 537 D Hindenegead) =2....4. 438, 443 BosterriGNely: sccc.ese: 577, 583 Dahlen see. ee 173, 174, 175, Fowler, G: Hoes 63, 72 7,201 Frey, We COR ae 434, 438, 439, Paley or eae ee ee 275, 276, 280, 443 2820 ortose Nei eee 171, 490, 492, WamottestR: ..5... 266, 268 498 Danas TID 463, 468,484 Fitterer, D. ................ 148 Danielopol, D. L. ........ 48, 59, 60 Daniels, C. H., von .... 148, 149, 163, G 165) ‘Gasliang. eM. 2.. 305, 306 DanbysiD AGS... .iss0s0.00: 130; 136 ‘Galfsoff PXSS: ....... 132, 134, 136 Darwant Ce 22. sscceccossoes 332"3a9) Gamiseiet: COR... 434, 443 DavishGs MAG. oc. sscc058t 219) (Gauthier se 45 Dave Jivbs oa eee 466,484 Gerlach, S. A. .............. 359, 366 Wefan PACT. .5ecssans- 467,484 Gervasio, A. M. ............ 411, 415 devFerraris, €. .22..2. 3194339) WGillbyaedee Vin eee 434, 443 D@SeTISPE TEE veccccescsssacee 142,144 Gladkova, I. G. ............ 402, 416 638 INDEX AUTHORS Glintzboeckel, C. ........ 290, 292,296 Henningsmoen, G. .... 45 (CON Ee Oa 473,484 Herrero Ducloux, A. .. 319, 339 Gramm M. N. .........:.. 219), Herrigay Wis ae. 78, 85 CAV ae Bi 8 csc cncncs-- oc 465; 46644695 Enll Belew: 25 91,97 G4 5466 ern Zens ©. meee... oeseeee 148, 164 TENOR OE. et .. ose.sosecracs OSLO Se aot. Cy ...3. sere iis aval Gregory, M. R. ............ Sieh Sia) TRIO KIN DG Ca secccsencoonen- 330, 337 Grekoff, INR A ce 8S, SOO TOOOR TLIO] eerie bates eee 87, 88, 90, 91, Grigor. ois: ....0-s 369 92, 93, 95, 97 (Eng0\e| 0210 BLOF oOr me LOrikostie Mion 257, 262 Grosdidier, G. .............. 268 Hornibrook, N. de. B. 332, 339 Grossman, S.. ..........:.:: AUGS454> Howe ndes....aee eee 62, 72 OW Ca Hi Wih ton co- ccs ccerek 268, 384, 414, H 415, 632, 634 ee 163. 164 Owes de (Cnr cee... 62, 72 oe edie we, eruliieeg ce” 476, 485, 493, 180, 182, 191, re 192, 193, 194, Ee eChinsiy lay Wine eeee 482, 485 197, 199, 200, 201, 203 I Hall, © A $65,468, $84 Heormoto, No 530, 521 Hanaitet 0... 509,520 Imbrie, J. 110, 122 Hancock, D. A... 134,136 Ishizaki, K. ............. 139 JEG. Jk eee 130 J [Blane Whar Al, Jes oe een 533, 535, 537 Hart, C. W. ............ 59,60 ~ Jacobs As Fe .i.cece 306 Hart, De o..ee. SIAGM Jacobi Cs ».....ccesere 290, 292, 296 63, 72, 214, 215, 275, 276, 280, 334, 335, 337, 339, 353, 3959, 356, 358, 359, 366, 492, 498, 501, 502, 509, 510, 514, 515, 517, 520, 551 Schroder, G. 355, 359, 366, 514, 520 aS KanSeu Cm Wisieeeeeces 271, 279, 280 Hathaway, J. Ff. ......0... 470, 472, 473, 484 ET ee We Wie, eee cecnca. cee: 552, 554 AZ ele SES) -eiestesseee 129, 130, 144, 369, 375, 383, 387, 401, 405, Table 6, between p. 406-407, 411, 414, 463, 465, 466, 468, 475, 476, 481, 482, 483, 484, 485 134, 137 629, 634 Hartmann - Hedgpeth, J. W. ........ Hennings Wr sos JohnsonCy Wee 468, 485 JONES™ MME occ e 130, 137 Jones Ts Re eno 87, 88, 90, 91, 92, 93, 95, 97 109, 110, 111, 122 ORG ane bee ee 371, 374, 375 WondankoHs, vee ae 286, 296 Jorgensen, N. O. ........ 530, 537, 552, 554 Tiwari, 125 epeenes vSaso0ee 268 K Kaasschietter, J. P. H. 328, 339 aeslery he) Wie 155, 164, 225, 226, 234, 242, 243, 475, 485, 578, 579, 580, 583, 626, 634 EUG OM bee 389, 414 Kawacubigises. 2 530, 537 TCBNGIANIEL, US” ceganseanereonece 218, 221 IKCONHPNE Co. ooocsscsssuc OAs IA), BATA 272) 206209) 280 ECE ka KG 578, 583 VeCCUITIPEN Pil BS 87, 88, 89, 92, 93, 97 639 INDEX AUTHORS Ireslings RS Vii so Ga- oe «© LiepauleAr es. 2h. 77, 79, 85, 86, 72, 87, 88, 89, 165 92°93) 978229" Ihippsied. Fe oo ieee 8 579, 583 2455625634 Looe whee 218, 219, 220, WRUenyioe eee 214, 216, 226, 221 243) Tockesaite. 42 eee 530, 537 Kincaid) 1se37) LotilersH. 2. 139, 434, 436, 1TH seg. Cal DBAS na ae 135, 137, 490, 441, 442, 443 492,493,498, Loosanoff, V. L. ........ 132, 134, 137 499) Torenz.).C., (osccn 290, 292, 296 Kansai 520 Lowenstam, H. A. ........ 577, 583 Tere Ob fe 855 sept 294, 295,296 Ludwig, W. ................ 227, 243 KIEKDY. 0; Ws tee 109, 11071 Luterova EB. A. 0. 219, 221 1995 “uke. (Bi Mae eee 530, 538 1 t=) | ce ee ee 353, 354°506.) Liodim (Ror. .::...2.. 89, 90, 91, 92, 383, 386, 387, 97 396, 398,414, Lutze, G. F. ................ 149, 164 409406" Laz Boe OOF nc: 552, 554 Klingebiel, A. ............ 411, 4139 Lyeikies Ot.............% 303 dito Ce 625, 635 M WKormeker:124S; 22.282 130, 135, 138, MacDonald, H. C. ...... 434, 442 139, 192,201, Maddocks, R. F. .......... 353, 354, 356, 217, 218, 219, 366, 399, 414 221, 374,490, Malek, S. R. A. .......... 530, 537 492,493, 498, Malloy, Jo. v.00... 330, 340, 411, ; 499, 535, 537 415 KROPTUN SAPS is. cinacesstee.a: 135;,137- Malagmian, N. J2...5.0... 328, 332, 339 Krandijevsky, V.S....__ 87, 88,89, | Mandelstam, M. I. .... 389, 414 91,92; 93,96,- Margerie, Bs... 271, 278, 279, 97 280, 290, 296 Geli Ger eae ae re 88,90,97 Marinoys (Peis -.......... 358, 367 Kirempy Gap t..2 A acs.: TIO} 23) Marsal Die. 110, 123 Krommelbein, K. ........ 242, 243,355, Martinez, C. G. ............ 319, 340 367 Martinsson!SA. ........: 63, 72, 85 Kummerow, E.......... 38, 90,07 Mastic © Ve00.... <.:.:.5.-. 327, 340 Kuznetsova, Z. V. ........ 389, 414 Maturot ies .S, 465, 485 Mazzoniy cA =). S2ieook L McKee Ja He oe tee 241, 243 McKenzie, K. G. ........ 112, 121, 242, Lammers, G. Fo 306 243, 624, 630, Tsaye wills eek ee ee PAG}. ARAL 635 ThamiyseB) oo. ee ss 218,221,411, McMillan, N. F.. ........ SPs Vis Y/ 413 Meischner, D. ............ 148, 149, 163, Wamgers Wares 552, 554 164 MatouchessCs AVie4i3n Melloyvts. (Bes oe 475, 485 aurencichets. 0. O68s ‘Mendez alswr.....:.:0-: 327, 340 mauziers 1 sMy oo 467,484 Menendez, C. A. ........ 324, 326, 331, Thay yee. 2 Rees. 290, 292, 296 340 Tey yOIeM, oss sees 389,'402"403) MerciersHe..27....2.... 290, 292, 296 414,416 Milliman, J. D. .......... 469, 473, 485 ThewiSs JH eM, ¢scsees. 134,138 Milo Di Villagrazia, P. 148, 164 We wise de RAR. cscs 176,201 Milyukova, N.N. ........ 402, 414 Lewontin’ R. Cs 2... 70, 72,253, Mingramm, A. ............ 319, 339 262 Mistakidis, M. N. ...... 134, 137 Lezeaudrei sy 2oessssccee 29052928296 Miyanos Ke... ne. 552, 554 homer weAdL..--..5...5 290; 2925296: Moberly, (Ra 222.2... 578, 583 640 INDEX AUTHORS Moquilevsky, A. .......... 20 Ra He Date ciencceeeen pees 148, 149, 164 Montgomery, M. P. .... 4665484 Penny,iL:. F...f.:..00h5 404, Table 5, No a a 268, 624, 635 between p. Mordukai-Boltovskoi, F. 406-407, 413 219220 Pessagno; tH» An .....: 552; /504 Morea J: P. ............ 303, 304305. Pettibone, M............. 130, 134 306 Peypouquet, J. P. .... 384, 387, 411, Morkhoven, F. P. C. M. van 414, 415, 447, 16, 45, 121, : 460, 461 123, 268, 374 Philpots, eels. scxstisrciar: 132, 134, 138 Morms. KR. W.. .....0...:.. 91,97 Picken, Te eel Re 536, 538 Wey eee ec. loccok 384, 411,413, Pilkey, O. H. ................ 469, 485 414,447,460. Pinto, 1). Dy 2.22.25) 48, 52, 56, 57, aot. © 60 MuhImann;) PP .......:.:. Sions4g «= Pisetta, Ji Le nce 333, 340 LTS all Oe 48,56,57,60 Plusquellec, P. L. .... 247, 262, 476, NTE TAS GEO 'Wie, <.ahess::-: 354, 367, 383, 485, 609, 611 306.414 Pokorny,.V."....0%..<:. 121, 123, 268 Migrrays Je Wie ..:..-.-+--. 553,554 Polenova, E. N. ........ 90, 91, 98 Pollandireeebaw eee 109, 110, 111, N NG, APA L ee 1 oh) ea ee 4 123 A ad ioe lee iay, Poulsen) WM 2... 354, 367 145, 216,384, Pourmotamed-Lachtenechai, F. 389, 404. 414, 268 415. 417 Przibram, 15 (peeene eeneer 63.72 MeCN Ls... G00; Put HeSo ete. 330, 340, 411, Nelson, J. R. 130, 135 215, 416, 285, Neville, AC... 530, 531, 535, 485, 490, 496 536, 537, 538 208: SL Ete ce toa commer Bumnee Tn ae 49, 52, 56, 57, Norman, A. M. ........... 383, 389, 413, at 415, 509, 520, R 623, 624, 632, 634,635 “Radkes MG: ...2....2%... 218, 221 re) Rees, CHB cee 397, 415 OuiEsE a er 134, 137 RUGISS Zee cone ree 552, 554 : Reymentyk, oo -eerssec- 367 Odreman, Rivas, O. E. 321, 327, 330, Reyment, R. A. ............ 64, 69, 72, Spl SB, an 141, 142, 143, Bertie Joo 368 Panne OUI 7 202553 cncsedanas 173, 174, 175, 367, 473, 483 201 Po si Beets One 173, 174, 175 Ohmert, We occ ccs ong, 206 FY 8 ie oases Omatsola, M. E. .......... 141, 144, 353, ” 2367 394, ei. ao Ribbes P He gs hnscvte 579, 583 , rehands: Av) Guiecs.-2 530, 532. 538, Orlov, Y¥. As cece G22 (a5) ERD ae De) 606, 611 Orionews He see. 134,138 Ritzkowski, S. 271, 278, 280, P Rartenoti “AG... 290, 292, 296 Rascuala Reece cee 3210327, 230; 331, 332, 334, 340 286, 290, 296 Se J 132, 136, 395, Table 5, between p. 406-407, 413 130, 132 Robertson, D. JENA ON, LIS cccconceptocerte 641 INDEX AUTHORS Robson}. (G.iC..........2. 132, 134, 138 Rodriso, FS ..... 3 319, 340 RoextATTinet, ic:-c ee Th, 74, PASS} 262 ROMER snc. 231, 234, 243 ROW ene ae 319, 339 ROMER ERS «2... Shoat 411, 415 ROSS GDR AL Bo ccciscncke 469, 485 Rossi de Garcia, E. .... 332, 333, 334, 335, 340, 502, 515, 520 ROGHMBR. TS sssscsscceecoe 88, 89, 90, 91, 98 Rowell) AW J. 4.0 624, 626, 635 RUSSelR Hie tS) os. seer 19, 45 Ryuniina: ee len ee 402, 416 S Sandbercwwee Ae 63, 64, 72, 138, 206, 207, 213, 214, 215, 226, 230, 243, 247, 262, 286, 287, 291, 296, 476, 485, 486, 493, 498, 699, 611 Sansa GO eee ee 215).200) Dit, 570 Schafer hs Were 205, 209, ae 216 Schmidt, R. A. M. .... 389, 415 Schneider, G. F. ........ 389, 414 Schneider so. 148 Schnitker, D.............. 465, 486 Schroeder, E. H. ........ 467, 468, 486 Schwerdtfeger, F. ...... 148, 149, 164 SCOURGE Wis etbcescccee nhl ales ScOttwilsae ee ee 382, 394, 416 ShayAGe lee. eee 306 Siddiquil@ cA] =... 369 Siclere ee oe = 625, 634 Simonatoelab. 319, 339 Simpson, G. G. .......... TUS UPA A BY 262 Skinner veh esc cee 530, 538 SHAT G HS ee EL. ese dees. 191, 202, 203, 498 Smit heerlen Vien ee 132, 138 Sneath welaeAceeee 624, 626, 635 Sohn Fiy GAS ss oooecseeeseoe 63, 64, 72, 130, 217, 218, 219, 221 Solcalt@e Res occas 231, 234, 243, 623, 624, 625, 626, 635 Spalettij) M.023..-= SAI, air Spjeldnaes, N. ............ 63, 72 Stanleya 0 Did ee BY AL Bi Stchepinsky, A. ........ 271, 280, 286, 287, 296 Stefansson, V. ............ 466, 467, 468, 486 Stephensen, K. .......... 383, 416 Stephenson, T. A. ...... 468, 486 Stephenson, A. .......... 468, 486 STEUTR GL aad a 436, 443 Slipanicie Ps Nee 319, 340 Suarez, Soruco, J. R. .. 334, 335, 340, 350 Suero.. Wee 5. eee 319, 339 Summerson, C. H. .... IO 128; Swans wee Vine 90, 91, 98, 135, 138, 269, 389, 416, 434, 443, 476, 484, 486, 492, 498 Swartz. be Vere eee 87, 88, 89, 90, 91, 92, 93, 96, 98 Sylvester-Bradley, P. C. 79, 86, 247, 262, 291, 296, 538, 551, 552, 553, 554 SZCZECIHUT Ad sme ee abe Pal es 123, 226, 244. 294, 297 rf jheissen, (BSE 149, 150, 155, 163, 164, 192 Thompson, D’Arcy W. UW5)s aks 45 Thompson, J. M. ........ 134, 138 Mressler, Wi Ts s. 60, 191, 202, 203, 401, 416, 498 Triater dss Mie o.oo 294, 297 Triebels cB, a ee 357 (Table 2), WSO Pc. e kes 311 307 630, 631 iO WP Ob Speer ee 311 307 Spy MOV oe oe ee 388, Siliege ts. Suieita antes 476 (Table 6), ADYSSOLUMI sees. sees between between 402-403 405-406 (Table 4). 408 408 SO salt at eee 329, 357 (Cytherelloidea) es. oe ce en eh Samoa’: Soo care Beet? Macher ee 377 135, 374, 447 dordonensis ............ 266 ; : 1 162 Faveolata cikere.... 110: mioe, (0, ane veiot 154, 155, OlOSa wee ee 356 frequens ................... 155 Bratt... es 265, 266 MIN OL 355, 360, 368 cf. ovata ....561,565 560,564 Cytheroma ................... 628 Gh punctate ts..nc. 361 (Table 2), sp. aff C. utilis 346 325 fet 6 630, 631 WENIGAGA occ svicccpiseteesse 150 WATIAIUIS S45. ee 154, 160 654 INDEX GENERA AND SPECIES Cytheromorpha .......... 411, 601, 602, 607, 609 Spr lds cet: 302 BT, Cte between 286-287 (Table 1), 289-292 SID tec or ks between 405-406 (Table 6) Cytheromorpha? TIMERS smartiae os. 345 323 Cytheromorpha cf. apheles: .....#.02....: 311 307 [ORWIUTTIE eke oe ene tae 276, 279 CHISEL) Siete Renee 287 ““Cytheromorpha”’ Caudatay 2. ccc.. 315 308 Cytheromorpha CUIgtar FRE sack. 377 374 aff. C. curta 607, 616 603, 605 (Table 1), 607-610, 617 macchesnyi ........ 423 388, 409 newportensis .......... 476 ouachatensis .......... 287 (Table 2) paracastanea ............ 287 Cytheropteron ............ PA NOSE Saye 384, 394, 404, 410 SOMES ee 377 374, between 402-403 (Table 4) STD eons e sce eaedenss between 405-406 (Table 6) SDeenOVe 2 tae 388 SpeenOve 2 ....... 428 LS] O)s | bi BRO nee ener e 310 307 SDaecee ea 310 307 SpRyAc (PP cs 476 SPEeDr eet. 476 ansulatume.. es 394, between 396-397 (Table 2), 398, between 402-403 (Table 4), between 405-406 (Tables 5, 6), 408 655 arcticum ....428, 431 arcuatum benedictus! 2]... crassipinnatum ........ dimlingtonensis dromedaria ebutemettaensis hamavumy ees > ee horacecoryelli ...313 inflatum ef. inflatum latissimum montrosiense 384, 388, 389, between 402-403 (Table 4). 404, between 405-406 (Table 5), 407, 409 between 405-406 (Tables 5, 6) 333 446 .. 384, 396, 397, 404, 405, between 405-406 (Table 5), 408 401, between 402-403 (Table 4), 408 356 396, between 402-403 (Table 4), 408 307 384, 395, between 396-397 (Table 2), between 405-406 (Table 6), 408 between 405-406 (Table 5) 395-397, between 402-403 (Table 4), 404, between 405-406 (Table 5) 397, 402, 404, 405, between 405-406 (Table 5), 408, 409, 411 INDEX GENERA AND SPECIES aff C. newportensis 333 nodosoala- Cuneo 428, 431 384, 387-389, 395, between 396-397 (Table 2), between 402-403 (Table 4), between 405-406 (Table 6), 409 atreG- nodosoalatum ....431 388, 389, 409 nodosum) 428 384, 398, between 402-403 (Table 4), 404, between 405-406 (Table 5), 408 paralatis- Simums 428, 431 384, 387-389, 395, 396, between 396-397 (Table 2), 406, between 405-406 (Table 6), 409 between 405-406 (Table 5) punctatum 395, between 396-397 (Table 2) cf. pipistrella ........ pyrami- dale: © .......: 388, 395, between 396-397 (Table 2), 398, 401, between 402-403 (Table 4), between 405-406 (Table 6), 407, 409, 476, 487 656 pyramidale ? .......... 395 cf. rhomboidea ........ 401, between 402-403 (Table 4), 408 rocanums 346 325, 326 rotundatum ............ 152, 156, 165 subcircinatum ........ 395 talquinensis ............ 476 VICLOMICMSIS’ 2.25...5 332 Cytherura ...220:6:... 358, 409, 496, 601, 602, 609, 610 Spas hiner ee 313 307, 611 SPD ete rerees between 405-406 (Table 6), 601, 610 NS SPb s225. 5c ee ee 335, 357 SD AL eee 476, 479, 481 Spf: .....:. 054. 342 476, 479 SPs cccast aes ees 477 SPUD... 36.245: 477 SPS be: onc Pei os 477 SDI ccc ee 477 SpiGun nets 477 SPE S 2 5 ti coe 477 SDrhat oa creiecceeee 477 Sp.LMee ec 477, 481 Cytherura aff C. COFreNsiS %2.2....0:<: 614 603, 605 (Table 1), 608, 609, 615 elongata ...... 377, 497 369, 373, 374, 476, 490, 496 490, 496 fFOTUlata eee 497 476, 481, 489, 490, 496 ef forulata = 614 603, 605 (Table 1), 608, 615 NOWEL> she... 476 JOHNSON see 497 490, 496 lilljeborgii, Hemicy- therura sp. aff. 350 335 ? mainensis ...... 379 374 MISTESCENS ................ 135 obliqua, Hemicy- therura sp. aff. 350 335 pseudostriata .......... 476 tajamarensis ............ 335 oman Gata seen 379 374 vestibulata..613, 614 603, 605 (Table 1), 608, 612, 615 WAU GIISIS iene 476, 481 INDEX GENERA AND SPECIES D dacica grekoffi, Hemi- Gyprideis ................ 285, between 286-287 (Table 1), 289-294 damottae (Cytherelloi- dea), Cytherella ...... 332 danaiana, Protocy- 1H OVES EY my ee ee 478 Daphnia galeata ........ 294 MELTOCULVA. .......00.05.00: 294 Darwinila 2... 592 437, 608 i: 595 273, 275, 277 dasyderma, Cythere .. 38Y/ daubjergensis, Globo- CONUSAN a aceccceseecncee 325 dawsoni, Actinocy- THETEIS: Fees. c.s.c5c05! 377 374, 476 GagiePeTila ...s..:....<03.. 356, 357 declivis, Eucy- ULOVE TRS) 2 SS en eee 379 375, 394, between 396-397 (Table 2), between 405-406 (Table 5). 446, 447, 487 deformis, Procy- tHeReIS=Ch oh... 2c: 293 delicata, Paradoxos- (OVOCE 6S so ae 477, 479 dentata, Cytheridea .. 396, 397 denticulata, Palmenella .............. 392 depressa, Xestole- OTIS cs. os sobensee: 423 200, 388, 390, 394, 396, between 396-397 (Table 2), between 402-403 (Table 4), between 405-406 (Table 6), 407, 409 dertobrevis, OxoQCconchal ee 152 dichotoma, Dictyoma 180, 186, 194 Dictyoma, dichotoma 180, 186, 194 dictyon, Bradleya ..29 20, 25 ?, Bradleya digitaris, Laminaria .. digitata, Laminaria .... 199 Digmocythere GUSSCHIP sce see 64, 65, 74 Dprisea, Garnosa «22... 187 dimlingtonensis, Cy- theropteron ............ 384, 396, 397, 404, 405, between 405-406 (Table 5), 408 dimorpha, Loxoconcha 356 discoidale, Eiphidivum ..........2 329, 335 discreta, Thlipsur- ella he. ae eee 90 Thlipsurella v- Scripta) Jose between 90-91 (Table 1) Thlipsurella? v- SCriptay icv eeeeees between 90-91 (Table 1) disjunctus, Scelerochilus ............ 356 dispar, Macrocypris .. 360 dispersocostata, Callis- tocythere ... 523, 526 356, 362, 501, 502, 504-507, 509, 514, 515 Dolocytheridea bosquetiana ............ 265 CEASSA tt ese: 266 dordonensis, Gythereis ©5%......35 266 Cytherella 22: 266 Dordoniella Stranculataw 266 dorsoserrata, Paradolorias 360 dorsespinata, Gythereis’ 4) Se-- 266 dromedaria, Cytheropteron ......... 401, between 402-403 (Table 4), 408 dubia, Patagonacy- (AYE aS) ale ae 404, between 405-406 (Table 6) Dumontia incrassata .. 181, 186 Dumontina Cenomlanae 266 INDEX GENERA AND SPECIES dunelmensis, Acan- thocythereis ...... 419 387-389, 392, 394, 396, between 396-397 (Table 2), 401, 403, 405, between 405-406 (Tables 5, 6), 407 Trachyleberis .......... between 405-406 (Table 5) E ebutemettaensis, Cytheropteron ........ 356 Echinocythereis .......... 30, 32, 330, 332, 334, 337, 609 Echinocythereis SPMEEt.o 8 566, 569 567, 568, 580 (Table 1) Silt digress UNE RES: fr ae 328 Rp Ane eee 477 boltovskoyi .............. 332 rite, 1h clarkanaul......2: 602 603, 605 (Table 1), 609, 621 jacksonensis ............ 65 margaritifera ...313 307, 477, 478 planibasilis procteri 477 spinireticulata 313 307 Eetocarpus’- 181, 182 i] Ora eaten ee 186 edulis, Ostrea ............ 134, 135 edwardsii, Costa ........ 410, 411, 445 Cytheretta ....... 377 374 edwardsii, Costa .... 446 Pseudocytheretta .... 478, 481 ehlersi, Haplocy- theridea = = ..2 as 64 ellipsoclefta, Phlipsurella ....:...::. 89, 90 elliptica, Hirsch- manniaewes se between 405-406 (Table 5) Loxoconchal 197, 447 Elofsonella amberii .. 285, 286, between 286-287 (Table 1), 289-291, 294, 298 concinnase 379 200, 374, 396, between 402-403 (Table 4), 404, 405, between 405-406 (Tables 5, 6), 408, 411 elongata, Cushmanidea .......... between 405-406 (Table 5), 445, 447 Cytherura 377, 497 369, 373, 374, 476, 490, 496 Mesocythere ............ 502 Elpidium: ..............8008 47, 49, 50, 52, 53, 55, 59, 60 discoidales =e 329, 335 NOS IA. ete see 48, 51, 53, 56, 7,59 MPOSP SEB: ee eee ee 48, 51, 53, 54, 58, 59 NASPMGy fe... ee 48, 53, 59 bromeliarum .......... 47, 48, 52, 56, 57, 59 emaciata, Carinocythereis ...... 446 COStAn & ccc eee between 405-406 (Table 5), emarginata, Baffini- cythere ...... 377, 420 369, 374, 381, 387-389, 394, 395, between 396-397 (Table 2), 398, 400, between 402-403 (Table 4), 404, 466, between 405-406 (Tables 5, 6), ensiforme, 409, 487 Paradoxostoma ........ 176, 181, 186, 188, 189, 193, 388, between 405-406 (Table 5), 447 658 INDEX GENERA AND SPECIES Enteromorpha ............ 180, 184, 192, 195, 197, 504- 507, 517 Glathratar = ...525... 180, 186, 194 GOMIPTeSSA ........0::.::-- 180 entrerriensis, BoNtONTaN c.-...-c. 332 entzheimensis, Cypridopsis) -......... 278 Eocytheropteron ........ 20521 bruggenenee ............ 293 ericea, Cythere .......... 337 Erpetocypris sp. ........ 436 (Op) Ghee eee ed ta aie) 437 Eucraterellina RanGdolplhit <............0< 90,,91 BWIA OIG) aconsccnaceecohesedee 274, 275, 280, 283 S05 - aa. ane Ae 275 amoyedalae oie... PTT), DRS} SPISVENSIS) o...-.0s00.-035-- 285, 278, 279 between 286-287 (Table 1), 289-291, 294, 298 Cfaserisiensis: .......... 279 pechelbronnensis .... 278 tenuistriata ............ PAIL, Parisi, 275). 277-279 cf. tenuistriata ........ PUPA, PAB}. 9475). Panta tenuistriata straubi 278, 285, 286, between 286-287 (Table 1), 289, 290, 294, 298 HUI CVUNCTO tes. oeesses, tet 610 SDH SMe ee. 313, 614 between 402-403 (Table 4), between 405-406 (Table 5), 603. 615 STD tee ace eceene between 405-406 (Table 6) (5) CARER REE ean ae eee 307 STO MASP ech sace reeeheiae: 477 dechivis; —.... + 379 375, 394, between 396-397 (Table 2), between 405-406 (Table 5), 446, 477, 487 477 triangulata 477 sp. aff. E. tri- angulata ....313,614 307, 603, 605 (Table 1), 607-609, 615 394 gibba Cn ataeeeeeee Eucytheridea 386 bairdii 387 Dradiiieaeeae 379, 424 375, 387, 388, 392-394, 396, between 396-397 (Table 2), 400, 401, between 402-403 (Table 4), 403-405, between 405-406 (Tables 5, 6), 408-410 macrolaminata ..423 387, 388, 390, 392, 393, 400, between 402-403 (Table 4), 406, between 405-406 (Table 6), 09 4 Rie he 424 381. 387, 388, 392-394, 396, between 396-397 (Table 2), 399, between 402-403 (Table 4), 403, 406, between 405-406 (Tables 5, 6), 409, 410 punctillata Eucytherura Euphilomedes PUAAORINGL psoaadooubssanscbnne ?Eusarsiella, n. sp. .... 659 Euthlipsurella Euthlipsurella angulata curvisiriata. ..........-... BOSSA GATS. ot oosobet susie’: INUIFICHT Va ......s.c.002-02 MNT CAGA Re oss see once: plicata bipunctata .. plicata unipunctata tuberosa evax, Henryhowella isa ited 6 [elect ns kee excellens, 345 Cythereis? exilis, Ambocythere ...311 Exogyra columba ...... F Fabanella cf. bolonien- SISH Se ne 573, 574 fabulina, Carbonia .... var. altilis, Carbonia var. humilis, Carbonia var. inflata, Carbonia Cypridopsis! 4 Falunia sp. ..566,574 sphaerulolineata .... fasciata, Neocy- therideis fasciolata, Candona .... fascis, Hetero- DLidGlSa ee ee INDEX between 90-91 (Table 1), 91, 92, 96 between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1) 332 323 307 263 572, 575 110) 101 110 110 110 tit 567,575 293 447 59 between 402-403 (Table 4), 408, 593 GENERA AND SPECIES fastigiata Furcellaria .............. 184, 186, 190 Fastigatocythere fullon- ica 558, 562, 569, 570 559, 563, 568, 571 faveolata, Sahnia 379 375 felix, Cyamocy- theridea fennica, Paracy- BTIGCIS) setae ferax, Xestoleberis .... fertilis fertilis, Can- dona (Pseudocan- dona) 278 filum;..Chorda #2:422 187, 190, 191 finmarchica, Finmar- chinella 379, 420, 423,424 _... 375, 384, 387- 389, 395, between 396-397 (Table 2), 400-402, between 402-403 (Table 4), 404, 405, between 405-406 (Tables 5, 6), 407, 477, 487 Finmarchinella 257 angulata ....419, 420 384, 388, 391, between 402-403 (Table 4), 404, 405, between 405-406 (Tables 5, 6). 407 325 394, 410 360 barentsovoen- SiSifeebe ce eee 419 384, 385, 387- 389, 394, 401, between 405, between 405-406 660 INDEX GENERA AND SPECIES Table 6), 407, 409 .. 81D, 804, 387- 389, 395, between 396-397 (Table 2), 400-402, between 402-403 (Table 4), 404, 405, between 405-406 (Tables 5, 6), 407, 477, 487 finmarchica 379, 420, 423, 424 fischeri, Callistocy- therev ee 502 Cytherois _........ 377 139, 374, 447 Cytherois aff. C. .... 154, 155, 162 Loxoconcha ........ 313 307 flava, Propontocypris 360 flexuosa, Paracy- GEE OIS pe ec eee 447 Paracytherois cf. P. 395, between 396-397 (Table 2), between 405-406 (Table 6), 408 flexuosum Paradoxos- (ACCETS ec ae eee 176, 186, 190 floridana floridana, Radimella? |....:...... 478, 481 floridana PUrianae 4 ce 478, 479, 481 Reticulocy- EHeETCIS eee ee 497 489, 490, 496 florienensis, Henryhowella .......... 6466, 74 forbesi, Moenocypris .. 273 forbesii, Candona ...... 280 fornicata, Crepidula .. 118P4, ISB; forulata, Cytheruraye 497 476, 481, 489, 490, 496 Cytherura cf. ...614 603, 605 (Table 1), 608, 615 fossata, Euthlipsurella ........ between 90-91 (Table 1) PE MIIPSUTA: Cac. meee between 90-91 (Table 1), 91 Thlipsurella ............ between 90-91 (Table 1) Thlipsurella? .......... between 90-91 (Table 1) “Thlipsurella”’ ........ 102 Fossocytheridea .......... 269 fournetensis, Cythereisi. eee 266 foveata, Mesocythere 502, 507, 508, Ban foveolata, Cytherella .. 110 foveolata, ‘“Sahnia” .. 478 fragile, Codium .......... 506 fragilis, Loxoconcha .. 410 frequens, Cytherois .... 155 frigida, Buccella ...... 335, 336 UCUS) eh lee eet 182, 200 SDD He)... 179 SETEAtUS! Gee le (, auch, teal. 182, 184. 186, 187, 194, 199 Spinalishy.8.es eee 199 vesiculosus .............. 175, 199 fullonica, Fastigatocy- there 7 562, 569, 570 559, 563, 568, 571 fulva, Microcy- tCheruraic.....2.... 197, 447 fISCHETI oe ee 313 307 fragilis 2.1225. 28% 410 cuttatarg.4ee s... between 405-406 (Table 5), 408, 410, 445, 446 INYDTESS AL ose 135, 410 lacinensisee eee 356 matagordensis ........ 477 megapora, n. subsp. 360 JPMDUDEKOVEE) sspcdehecdsoncee 410, 446 parameridionalis . 361 paranensis ........ 350 333, 335 purisubrhom- botdea é-- between 90-91 (Table 1) Sse 5 Seminars th 87, 88, 89, 90, Thlipsura between 90-91 92, 94, 96, 90-91 (Table 1) 682 binodosa confluens corpulenta curvistriata fossata jonesi multipunctata muricurva parallela personata INDEX GENERA AND SPECIES between 90-91 (Table 1), 104 88, 89, between 90-91 (Table 1), 93, 96, 100 between 90-91 (Table 1) 89 between 90-91 (Table 1) 87, 88, 89, 90, between 90-91 (Table 1), 91, 92, 93, 94, 95, 96, 100, 102, 104 between 90-91 (Table 1), 91 between 90-91 (Table 1), 91 88, 89, between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1), 92 90, between 90-91 (Table 1) between 90-91 (Table 1), 91 between 90-91 (Table 1), 91 between 90-91 683 plicata plicata var. bi- punctata plicata var. uni- punctata primitiva robusta robusta var. tri- cornis simplex striatopunctata subfurca tetragona thyridioides triloba ? triloba (Table 1) 88, 89, 91, 93, between 90-91 (Table 1), 91, 93, 96, 100 (Table 1), 93, 96, 100 90-91 (Table 1), 93, 96 90-91 (Table 1) 90 between 90-91 (Table 1) 90, between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1), 91 89, between 90-91 (Table 1), 91 between 90-91 (Table 1) between 90-91 (Table 1) 89 between 90-91 (Table 1) between 90-91 (Table 1) tuberosa weet eee rereeecces v-scripta ? v-seripta v-scripta discreta .. oeccccncccccee whiteavesi =...22-- Thlipsurella anemlataye see curvistriata .............. Pe GISer etal... ee. ellipsoclefta fossata ee TOSsSatae ne “Thlipsurella” fossata Thlipsurella multi- punctata muricurva (Table 1), 1 INDEX 90-91 (Table 1) between 90-91 (Table 1) 89, 90, between 90-91, 92 between 90-91 (Table 1), 92 between 90-91 (Table 1), 92 between 90-91 (Table 1) 92 between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1) 90-91 (Table 1) between 90-91 (Table 1) 102 90-91 06 GENERA AND SPECIES plicata bipunctata .. plicata uni- punctata ? simplex striatopunctata ........ tetragona .. ? tetragona tuberosa . v-scripta . ? y-seripta v-scripta discreta .... ? v-scripta dis- creta Thlipsuroides parallela striatopunctata (Table 1) between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1) between 90-91 (Table 1) 91 between 90-91 (Table 1), 91 INDEX GENERA AND SPECIES thlipsuroides ............ 91 Thlipsuroides .......... 91 thurneri, Spermo- iio 190 thyridioides, Neo- (Palit ys 0) cf: | See 90, between 90-91 (Table 1), 91, 106 MMONDSULA 22oo2k.6. hss. between 90-91 (Table 1) POUND ia ccccanstscceeonn- 337 Saree, 345 323, 326 australis) 220.0... 346 325, 326 torosa, Cy- prideis ....... 597 205-209; 211- 214, 445, 447 forma litoralis, CyPEIGEIS! sess 205 forma torosa, CyPTIGeIS xcs: sc0he0:: 205 torquata, Cly- mienellay ti. .ee:.cose ec 133, 134 Trachyleberis ............ 18h BBE aoe ? MES Dert feos ocscSacdibvs 345 322, 324 Cos Wh ae 329 GSl0S | 23 Aas te ena a 329 dunelmensis ............ between 405-406 (Table 5) ? montgomery- TIS (as re 61, 64-67, 69- 71, 73, 74 TEKONVE! Gisnc AS eee 333 princeps ............ 342 322, 324 WEIPEF ...........: 346 325 triangulata, Eucy- PET EIP 5 csccccsscsoredeeees 477 Eucythere hats gs eee 313, 614 307, 603, 605 (Table 1), 607-609, 615 tricornis, Craterel- lina’ (robusta? .”.=)..:. between 90-91 (Table 1) Neothlipsura ro- Mustay evar. ...-...sccc.: 90, between 90-91 (Table 1), 91 tricostata subsp. 1, (OSTA: 2 aes ees 293 Sarsiellag she osc 130 triebeli, Ilyocypris .... 322 trigonella, Pontocy- PISS, fete ce ce Es between 402-403 (Table 4) triloba, Thlipsura ...... 89, between 90-91 (Table 1) ThHpsSura?” a nid : = > a = Ps) : 3 m : = ~— wn 2 INSTITUTION NOILALILSNI NVINOSHLINS S31IYYV z 2) = x ” = wn 5 c = a fh = < = = = = \ 4 z = %Y D x re) : a3 Oo = - AA Z 2 >. INE S “2 3 : = 2 E Wy 2 = 2 yo a ee = Bie es = S NOILNLILSNI_ NVINOSHLIWS = S3 1YUVudl 1_LIBRARI ES SMITHSONIAN INSTITL ‘ ph J FA w FA = py, 5 - = oc = © ¥ a : = a . oo ws SS a 5 a 5 4 = a z — = LIBRARIES SMITHSONIAN INSTITUTION NOILNLILSNI NVINOSHLINS S3IY¥V : z a z r z 7 = ae) o SS 2) z “2 : : : Gy > : a E : - Gy 3 '- Fe SG g ; g f) pa ~” — wn ‘* -_ NOILNLILSNI NVINOSHLINS S3!1YVYdIT LIBRARIES SMITHSONIAN fy ae w = we: w z = re = sa = = : S = uf ty & . = 6 a : ee ae g 2 2 c 2 “yp = zZ = > = > = Cas = Z : 7) Fs a?, ag Nog ” LIBRARIES SMITHSONIAN INSTITUTION NOILALILSNI NVINOSHLIWS > nw S ” = sal n” n os Viena Rag’ Se) = n RNS pe 4 «. Ze a 4 SN ig ar < - hf - x 4 SS oN